Influence of stocking density on the performance, carcass characteristics and selected welfare indicators of broiler chickens

The effects of varying stocking densities during the first 10 days on the performance, welfare, slaughter and meat quality characteristics of broiler chickens in the subsequent period

This study aimed to investigate the effects of varying stocking densities during the first 10 days on the performance, welfare, slaughter and meat quality characteristics of broiler chickens in the subsequent period (11-42 days). In the study, treatments representing 3 different stocking densities with the same group sizes were established and a total of 432 d-old chicks were used. In the first 10 days of the rearing period, treatments of 18 (SD18), 27 (SD27) and 36 (SD36) chicks per m2 were formed, and at 11 days of age, chicks in all treatments were reared at a density of 18 chicks/m2. Body weight differences in SD18, SD27 and SD36 treatments at 10 and 42 days of age were significant (P < 0.05), they were 252.6, 254.3 and 241.5 g in SD18, SD27 and SD36 groups at 10 days and 2961.1, 2874.8 and 2842.7 g at 42 days of age, respectively. In the first 10 days of growing period, SD36 showed a significant difference (P < 0.05) from the other groups in feed intake and feed conversion ratio, but this was not significant at slaughter age. The livability at 10 and 42 days was not different among treatments and was between 98.6 and 99.3% and 93.5-93.8%, respectively. The uniformity at 10 days was significant among the stocking density groups (P < 0.05) and the best uniformity level was obtained in the SD36 group, the differences in CV values at 42 days were not significant among the treatments. EPEF (European production efficiency factor) values were not different between the groups, the highest numerical value was determined in the SD36 group. Foot pad dermatitis, hock burn and breast burn levels were significantly higher in SD18 chickens (P < 0.05), however incidence of finger crookedness and valgus-varus deformity did not differ between the treatments. The litter moisture contents were similar between treatments, and ranged from 25.6 to 32.6%. Different stocking density treatments during the first 10 days of the experiment had no significant effect on slaughter, abdominal fat, carcass parts, color and pH values in the breast and thigh meat. In conclusion, rearing broiler chickens by dividing the poultry house area by half during the first 10 days (36 birds/m2) could help to improve the overall productivity (EPEF) by providing ease of maintenance, efficient heating and better control.

Low-cost uncrewed aerial vehicles (UAVs) as a novel tool for welfare assessments on open pen commercial crocodile farms

BACKGROUND

The welfare of crocodiles on commercial farms in southern Africa requires precise assessment, focusing on stocking densities and pen conditions. However, disputes between animal welfare groups and farm owners persist due to inadequate methodologies for quantifying these factors.

OBJECTIVES

This study aimed to address these disputes and enhance crocodile welfare assessment by introducing a novel technique using a low-cost consumer uncrewed aerial vehicle (UAV) and open-source photogrammetry software. The objective was to quantify key welfare parameters accurately and efficiently.

METHOD

The study involved applying the UAV-based technique to two large Nile crocodile (Crocodylus niloticus) farms in South Africa. The approach enabled the mapping and surveying of crocodile pens, facilitating the determination of stocking densities, biomass indicators, and other pen-related attributes. Comparisons were made between UAV-derived crocodile counts and farmer estimates.

RESULTS

The UAV-based crocodile counts significantly differed from the estimates provided by farmers, underscoring the need for a more precise assessment method. The technique's cost-effectiveness was evident, with implementation expenses totalling less than R10 000, a fraction of the cost associated with commercial UAV surveys.

CONCLUSIONS

The introduced UAV-based technique offers a valuable solution to the ongoing debates regarding crocodile welfare on commercial farms. By quantifying key parameters accurately and economically, it empowers farmers and animal welfare groups to make informed decisions. The method's ease of adoption, demonstrated through its use by some Southern African crocodile farmers, signifies its potential for widespread application, ultimately contributing to improved crocodile welfare.

Immunoregulatory and antioxidant properties of tryptophan in quail chick

A dose-response assay was carried out to investigate the effects of graded levels of dietary tryptophan (Trp) on blood variables, immunity, and meat quality in quail chicks during the last two weeks of the growing period. A total of 420 21-day-old quail chicks were randomly distributed across the seven experimental groups (i.e., 2.12, 2.25, 2.38, 2.51, 2.64, 2.77, and 2.90 g Trp/kg of diet) with four pen replicates of 15 birds each. Blood variables, including uric acid (UA), albumin (ALB), and triglycerides (TG), responded inversely to increasing dietary Trp (P < 0.001). The concentration of aspartate aminotransferase (AST) in serum, the relative weight of bursa of Fabricius (BF), immunoglobulin G (IgG), water holding capacity (WHC), and antigen production against the sheep red blood cells (SRBC) increased with increasing dietary Trp (P < 0.001). In contrast, the concentration of malondialdehyde (MDA) and drip loss in meat samples decreased with increasing dietary Trp (P < 0.001). The best models for optimal dietary Trp were identified based on a statistical merit basis known as the model accuracy index (δ). The estimated dietary Trp for optimizing ALP, UA, total protein (TP), TG, SRBC, IgG, BF, drip loss, WHC, and MDA were obtained at 2.347, 2.371, 2,372, 2.485, 2,691, 2.738, 2.306, 2.359, 2.247, and 2.500 g/kg of diet, respectively. Principal component analysis showed that UA, TG, IgG, and drip loss had a higher association with dietary Trp rather than other responses. Considering the high δ and eigenvalues of the models, the best estimation of dietary Trp level required for the optimization of the studied traits in quail chicks would be 2.738 g Trp/kg of diet, which was significantly higher than that recommended for the quail performance by NRC (1994).

Assessment of Welfare Problems in Broilers: Focus on Musculoskeletal Problems Associated with Their Rapid Growth

The growth of the broiler industry has been accompanied with concerns over the environmental and social impacts on intensive production systems, as well as the welfare of the animals themselves. As a result, since the 2000s, there has been growing interest in alternative production systems that improve animal welfare and sustainability. In this context, it is important to prioritize the welfare of broilers in commercial production systems and to use reliable welfare indicators to provide consumers with information about the welfare of the animals they consume. Resource-based measures (RBM) are based on assessing the resources available to the birds in terms of their housing, environment, and management practices, such as stocking density, litter quality, lighting and air quality, etc. Outcome-based measures (OBM), also known as animal-based measures, focus on assessing the actual welfare outcomes for the birds, such as footpad dermatitis, hock burn, contamination or damage to feathers, gait score, mortality, etc. These OBM-based measures are one of the more direct indicators of welfare and can help identify any welfare issues. The present review highlighted the factors that affect animal welfare indicators focused on OBMs which can be used in the commercial broiler farms.

The Effect of Borage (Borago officinalis) Extract on Growth Performance and Immune System of Broilers at High-Density Conditions

The present study was conducted to investigate the effects of borage extract (BE) on growth performance and the immune system of broilers at high-stocking-density. A total of 330 male Ross 308 broilers were distributed in a completely randomized design with six experimental treatments each with three replications. Treatments were T1: 10 broilers/m2 (positive control group), T2: 20 broilers/m2 (negative control group), T3: 20 broilers/m2 + 150 mg/l of borage extract (BE), T4: 20 broilers/m2 + 300 mg/l of BE, T5: 20 broilers/m2 + 450 mg/l of BE, and T6: 20 broilers/m2 + 600 mg/l of BE. Weight gain, feed intake, and feed conversion ratio (FCR) were measured weekly and immune responce were examined twice. The use of BE could improve weight gain, feed intake, and FCR in broilers reared at a high-stocking-density. BE treatment improved the immune response of broilers. According to the results, the use of BE at 600 mg/l is useful in reducing the effects of density stress. Therefore, BE can be used as a nutritional strategy to improve the bird performance in stressful conditions.

Evaluating broiler welfare and behavior as affected by growth rate and stocking density

This study evaluated the welfare and behaviors of Cobb 700 broilers as affected by growth rate (GR) and stocking density (SD). Slower-growth (weight gain < 50 g/d) and medium-growth (weight gain = 50-60 g/d) broilers were produced by providing 57.1% and 78.6% of the feed intake listed in the Cobb 700 production manual for standard (fed ad libitum) broilers (weight gain > 60 g/d). Broilers at all 3 GRs were reared at 2 SDs of 30 and 40 kg/m2. Broiler welfare indicators, including gait score, tibia strength, feather coverage, and footpad condition were evaluated when birds reached 1, 2, and 3 kg of body weight. The activity index was determined by overhead cameras and image processing, and the time spent at feeders was recorded using the radio-frequency identification (RFID) systems. The results show that it took 45 d for standard, 52 d for medium-growth, and 62 d for slower-growth broilers to reach a 3 kg market body weight. Feed conversion ratios (FCR, kg/kg) were 1.57 for standard, 1.67 for medium-growth, and 1.80 for slower-growth broilers. Growth rate and SD had an interaction effect on feather cleanliness (P = 0.03), and belly feather coverage (P = 0.02). Slower-growth broilers were more active and had better feather coverage and gait scores than medium-growth and standard broilers (all P < 0.01) but may feel hungry and depressed, medium-growth broilers spent the most time at the feeder among the 3 growth groups (P = 0.02), and standard broilers showed the best production performance. Broilers at 30 kg/m2 showed better bone strength (P = 0.04), and footpad condition (P < 0.01) compared to those at 40 kg/m2. In conclusion, reducing GR and SD may slightly improve broiler leg health at the high expense of compromised production performance and prolonged production cycles.

Use of coffee husks - comparison of pellet bedding quality, performance features, and some welfare indicators of broiler chickens

BACKGROUND

The study aimed to evaluate the influence of wheat straw and different coffee husk (CHs) levels in pellet bedding on its quality, broiler chickens' performance, meat quality, and welfare indicators. In total, 200 Ross 308 chickens were divided into 4 groups: C - control with wheat straw pellet; CH10 - pellet with 10% CHs, CH25 - pellet with 25% CHs, and CH50 - pellet with 50% CHs. During 42 days of rearing, each bedding's physicochemical features were analyzed. The production results were controlled, and the footpad dermatitis, hock burns, and feather quality were assessed. From chosen birds, carcass composition was analyzed, as well as the qualitative features (color, water-holding capacity, drip loss) and breaking bone strength.

RESULTS

The bedding material and rearing days influenced the content of dry matter, crude fiber, nitrogen, phosphorus, potassium, NDF, ADF, and pH. The results were inconclusive. The increasing trends in nitrogen, phosphorus, and potassium content were noticed at the end of rearing. Strong coefficient determination in bedding features was found (0.580 - 0.986). The pellet with CHs had no adverse effect on the growth performance of broilers. In the CH50 group, a lower fat percentage was found. A beneficial effect on water-holding capacity was noticed in leg muscles from CH10 and pectoral muscles from CH25. A significant decrease was found in footpad dermatitis incidence in groups CH25 and CH50.

CONCLUSIONS

It can be concluded that CHs reuse in broilers as the pellet bedding material is possible due to the beneficial effect on some meat quality features and no adverse effect on the performance of broiler chickens. The positive impact on lower foot pad dermatitis incidence indicated the possibility of using CHs in pellet bedding.

Growth Rate Distribution and Potential Non-Linear Relationship between Body Weight and Walking Ability in Turkeys

The aim of this study was to investigate the potential non-linear relationship between growth and walking ability (WA). The phenotypic data included body weights at 12 and 20 weeks and WA at 20 weeks of age measured on 276,059 male turkeys. The growth rate at three age periods (0 to 12, 12 to 20 and 0 to 20 weeks) was calculated. Each bird was assigned to one of the quartiles of the growth rate distribution for each age period. Between the first and fourth quartiles, the incidence of score 1 (bad WA) increased by 31, 18, and 33% for the first, second, and third age periods, respectively. For good WA (scores 4, 5, and 6), the incidence decreased by 55, 66, and 72% between the first and fourth quartiles for the first, second, and third age periods, respectively. Estimates of heritability of WA ranged between 0.18 and 0.26. The genetic correlations between adjacent growth rate quartiles were high and decayed as the interval between quartiles increased. The magnitude of the variation in the incidence of walking scores and genetic correlations across the growth rate quartiles point towards a non-linear relationship between growth and mobility suggesting other factors may affect walking ability.

Effect of housing system and housing density on performance, viability, and gastrointestinal tract growth of broiler chicks during the first 2 wk of age

This experiment was conducted to study the effect of housing systems and housing densities on the performance and digestive tract growth of broiler chicks during the first 2 wk of age. A total of 3,600 Cobb500 day-old chicks were stocked at 4 densities (30, 60, 90, and 120 chicks/m2), and reared under 2 housing systems (conventional housing system and newly developed housing system), yielding a 2 × 4 factorial arrangement. The studied traits were performance, viability, and gastrointestinal tract development. The results indicated that housing systems and housing densities significantly (P < 0.001) affected the performance and GIT development of chicks. There were no significant interactions between housing system and housing density for body weight, body weight gain, feed intake, and feed conversion. The results also showed that the effects of housing density were age-dependent. That is, the higher the density, the lower the performance and digestive tract growth with advancing age. In conclusion, birds in the conventional system outperformed birds in the newly developed housing system, and further work is needed to improve the new housing system. To achieve the highest performance, digestive tract growth, and digesta content, a density of 30 chicks/m2 is recommended for chicks up to 14-days old.

Fast- and slower-growing broilers respond similarly to a reduction in stocking density with regard to gait, hock burn, skin lesions, cleanliness, and performance

There is an increasing trend toward broiler production systems with higher welfare requirements. Breed and stocking density are considered key factors for broiler welfare that are often specified as criteria for such higher welfare systems. However, it remains unknown how slower-growing broilers respond to a reduction in stocking density with regard to their welfare and performance, and whether this response differs from fast-growing broilers. Therefore, we compared fast- (F) and slower-growing broilers (S) housed at 4 different stocking densities (24, 30, 36, and 42 kg/m2, based on slaughter weight) and measured their welfare scores (i.e., gait, footpad dermatitis, hock burn, skin lesions and cleanliness), litter quality and performance. The experiment had a 2 × 4 factorial design with 4 replicates (pens) per treatment (32 pens in total). Thinning (15%) was done in a 50/50 male/female ratio at 38 (F) and 44 (S) d of age (estimated body weight of 2.2 kg). We hypothesized that breeds would respond differently to a reduction in stocking density. Contrary to our hypothesis, only one interaction between breed and stocking density was found on footpad dermatitis, indicating that fast- and slower-growing broilers generally showed similar responses to a reduction in stocking density. F broilers showed a steeper decline in the prevalence of footpad dermatitis with reducing stocking density compared to S broilers. Broilers housed at lower stocking densities (24 and/or 30 kg/m2) showed improved welfare measures, litter quality and performance compared to those housed at higher stocking densities (36 and/or 42 kg/m2). S broilers had better welfare scores (gait, footpad dermatitis and skin lesions), litter quality and lower performance compared to F broilers. In conclusion, reducing stocking density improved welfare of both F and S broilers, but more for F broilers in case of footpad dermatitis, and using S broilers improved welfare compared to F broilers. Reducing stocking density and using slower-growing broilers benefits broiler welfare, where combining both would further improve broiler welfare.

Welfare of broilers on farm

This Scientific Opinion considers the welfare of domestic fowl (Gallus gallus) related to the production of meat (broilers) and includes the keeping of day-old chicks, broiler breeders, and broiler chickens. Currently used husbandry systems in the EU are described. Overall, 19 highly relevant welfare consequences (WCs) were identified based on severity, duration and frequency of occurrence: 'bone lesions', 'cold stress', 'gastro-enteric disorders', 'group stress', 'handling stress', 'heat stress', 'isolation stress', 'inability to perform comfort behaviour', 'inability to perform exploratory or foraging behaviour', 'inability to avoid unwanted sexual behaviour', 'locomotory disorders', 'prolonged hunger', 'prolonged thirst', 'predation stress', 'restriction of movement', 'resting problems', 'sensory under- and overstimulation', 'soft tissue and integument damage' and 'umbilical disorders'. These WCs and their animal-based measures (ABMs) that can identify them are described in detail. A variety of hazards related to the different husbandry systems were identified as well as ABMs for assessing the different WCs. Measures to prevent or correct the hazards and/or mitigate each of the WCs are listed. Recommendations are provided on quantitative or qualitative criteria to answer specific questions on the welfare of broilers and related to genetic selection, temperature, feed and water restriction, use of cages, light, air quality and mutilations in breeders such as beak trimming, de-toeing and comb dubbing. In addition, minimal requirements (e.g. stocking density, group size, nests, provision of litter, perches and platforms, drinkers and feeders, of covered veranda and outdoor range) for an enclosure for keeping broiler chickens (fast-growing, slower-growing and broiler breeders) are recommended. Finally, 'total mortality', 'wounds', 'carcass condemnation' and 'footpad dermatitis' are proposed as indicators for monitoring at slaughter the welfare of broilers on-farm.

Stocking density-induced changes in growth performance, blood parameters, meat quality traits, and welfare of broiler chickens reared under semi-arid subtropical conditions

Broiler production in semi-arid tropics must contend with high levels of heat stress, which have implications on stocking density, bird welfare, and profitability. Under these conditions, optimal stocking densities are likely to be lower than expected, thus must be experimentally determined. Therefore, this study investigated growth performance, haematology, serum biochemistry, carcass and meat quality, sizes of internal organs, and stress biomarkers in response to different stocking densities in broilers reared under semi-arid subtropical conditions. Five hundred, day-old Ross 308 broilers (44.0 ± 5.24 g live-weights) were randomly distributed to 25 replicate pens (1.32 m² floor space each) to create five stocking densities: 1) 10 birds/pen (SD10); 2) 15 birds/pen (SD15); 3) 20 birds/pen (SD20); 4) 25 birds/pen (SD25); and 5) 30 birds/pen (SD30). There was a linear decrease (P < 0.05) in overall feed intake and weight gain in weeks 2 and 3 as stocking density increased. However, weight gain showed positive and negative quadratic responses (P < 0.05) in weeks 5 and 6, respectively, as stocking density increased. No linear or quadratic effects (P ˃ 0.05) were observed for overall feed conversion ratio, haematological parameters, and meat quality traits in response to stocking density. Symmetric dimethylarginine, alanine transaminase, and albumin levels quadratically increased (P < 0.05) in response to increasing stocking densities. Serum glucose and thigh weight were not affected (P < 0.05) while final body, drumstick, breast, and wing weights linearly declined with stocking density. Increasing stocking density linearly reduced (P < 0.05) the weights of gizzard, proventriculus, caecum, and colon. Stocking density had no effect (P ˃ 0.05) on latency-to-lie. It was concluded that higher stocking densities compromised feed intake, resulting in poor weight gains. Based on weight gain trends observed in week 5, it was determined that Ross 308 broilers should be reared at no more than 20 birds/pen (~15 birds/m² or 27.27 kg/m²) under the experimental ambient conditions compared to the much higher globally accepted industry standard of 20 birds/m².

Influence of Using Perforated Plastic Flooring Beneath the Waterline on Growth Performance, Litter Quality, and Footpad Health of Broiler Chickens: A Field Study

Simple Summary

The standard housing method in Europe’s poultry farming is to keep broilers on a littered concrete floor. Therefore, wood shavings are used to catch moisture to prevent wet litter. In particular, the broilers frequently visit the wet area beneath the waterline, where the wet litter causes the main problem in footpad health and animal welfare. The current study tested the impact of slatted flooring beneath the waterline by dividing the barn into three areas (drinkers, feeders, comfort) in terms of growth performance, litter quality, and footpad health of the broilers. The quality of the litter was assessed on the basis of different parameters, for example, dry matter. No effect on growth performance between a littered floor and partially slatted flooring was noted. However, the litter parameters show a small positive impact on the litter quality, especially in the areas of drinkers and comfort, while using partially slatted flooring. Nevertheless, the slatted flooring had an impact on the footpad health of the broilers, with a lower FPD score at the end of the fattening period.

Abstract

The aim of this study was to evaluate the effect of slatted flooring beneath waterlines in broiler barns on litter quality and, subsequently, footpad health. The hypothesis tested was that installing slatted flooring underneath waterlines helps to improve litter quality and thus reduces footpad diseases, enhancing animal welfare as a result. Five experimental runs with two groups were conducted. Each run was defined as one fattening period of 32 days and consisted of 15,000 broiler Ross 308 of both sexes. Every barn was divided into three areas (drinkers, feeders, and comfort area) for weekly sampling. No influence on growth performance was noted. The slatted flooring influenced the litter quality by preventing the litter in the experimental group (EG = 690 ± 167 g/kg DM) from becoming moisture until day 14 of the fattening period compared to the control group (CON = 636 ± 198 g/kg DM). The footpad health was also influenced by using slatted flooring, with lower camera-based footpad scores in the EG (8.80) compared to CON (22.0) at the slaughterhouse (p = 0.0258). Installing slatted flooring beneath the waterline reduced the moisture of the litter compared to the control barn in the first two weeks of age and showed a positive effect on the footpad health of the broilers at the end of fattening, which indicates an improvement in animal welfare.

Differences in carcass composition and meat quality of conventional and slow-growing broiler chickens raised at 2 stocking densities

The fast growth rate of broiler chickens is a welfare concern that has increased consumer interest in chicken from slower growing (SG) broilers. Replacing conventional (CONV) broilers with SG broilers will reduce chicken supply and SG broilers require different management practices than CONV. This study evaluated the effects of 2 stocking densities on the carcass composition and meat quality of CONV broilers that reach market weight at 42 d and SG broilers that reach market weight at 63 d. Male broilers from each strain were exclusively stocked into 16 pens at a density of either 29 kg/m² or 37 kg/m². Live body, carcass without giblets (WOG), and part weights were recorded and used to calculate yield. Initial and 24-hour pH, color (L*, a*, and b*), cooking loss, and Warner Bratzler shear force of the breast and thigh muscles were measured. Birds from both strains reached similar live body and carcass WOG weights. CONV had 3.4%, 13.0%, and 2.8% greater (P ≤ 0.002), carcass WOG, breast, and tenderloin yields, while SG had 2.7%, 5.0%, 7.5%, and 1.2% greater (P < 0.0001) wings, leg quarters, frame, and skin yields, respectively. CONV breast 24-h pH and cooking loss were greater (P ≤ 0.04) than SG. While SG thigh shear force was greater than CONV (P = 0.008), breast shear force was the lowest for CONV stocked at 29 kg/m² and the greatest for SG stocked at 37 kg/m² (P = 0.04). SG had a paler breast than CONV, while CONV had a yellower breast than SG (P < 0.0001). While SG had a redder thigh than CONV (P = 0.002), SG stocked at 29 kg/m² had a redder breast than SG stocked at 37 kg/m², with both CONV groups intermediate (P = 0.04). These results indicate that differences in male broiler meat quality were affected more by strain than by stocking density. Compared with CONV, SG broiler meat quality was more affected by stocking density in this study.

Dietary strategies to alleviate high-stocking-density-induced stress in broiler chickens – a comprehensive review

Stocking broilers at a high density has been a strategy to optimize the area of the cage and hence increase the efficiency of broiler production. If the environmental (microclimate) conditions and rearing management are not properly managed, stocking broilers at a high density may, however, result in stressful conditions that are harmful for the production, health and welfare of broilers. To ameliorate these unfavorable effects of overcrowding stress, dietary interventions have been conducted. Probiotics, prebiotics, synbiotics, plant-derived products, vitamins, propolis, amino acids, fatty acids, etc. have been supplemented in diets to deal with the harmful impact of stress induced by a high stocking density of broilers. This review covers the detrimental effects of overcrowding-induced stress on broiler development and attempts to ameliorate those negative effects by dietary interventions.

Impacts of tea tree or lemongrass essential oils supplementation on growth, immunity, carcass traits, and blood biochemical parameters of broilers reared under different stocking densities

The effects of tea tree essential oil (TTEO) and lemongrass essential oil (LGEO) with different stocking densities on the growth performance, biochemical markers, antioxidants, and immunity state of broiler chickens were studied.  Birds were housed at stocking densities of 25, 30, 35, and 40 kg/m². The treatments were, basal diet without any supplementation, the second and third groups were supplemented with 300 mg TTEO/kg feed, and 300 mg LGEO/kg feed, respectively. Results revealed that increasing stocking density from 25 to 40 kg/m² significantly reduced body weight and daily weight gain at different ages. The phagocytic index and activity were significantly higher under the lower stocking density (25 kg/m²). Serum amyloid A (SAA), serum or liver transferrin (TRF), or C-reactive protein (CRP) were significant decreased when decreasing stocking density. Increasing stocking density from 25 to 40 kg/m² resulted in a significant increase in the serum urea, creatinine, uric acid, lactate dehydrogenase (LDH), alanine aminotransferase (ALT), aspartate aminotransferase (AST), malondialdehyde (MDA), and catalase (CAT) levels. However, there was a significant reduction in antioxidant enzyme activity, including glutathione peroxidase (GPx) and superoxide dismutase (SOD), as stocking density increased. The supplementation of TTEO produced significantly higher body weight and daily weight gain followed by LGEO. Additionally, the mortality rates were reduced in TTEO (27.4%) and LGEO (25%) groups. TTEO or LGEO supplementation significantly improved meat constituents and cellular immunity and reduced serum total lipids, serum and meat cholesterol, and triglycerides, SAA, TRF, and CRP. For all these measured parameters, superior results were obtained when TTEO was used compared to LGEO. TTEO or LGEO supplementation also significantly reduced serum urea, creatinine, uric acid, and the enzymatic activities of LDH, ALT, AST, MDA, and CAT (but not GPx and SOD) in comparison to the control treatment. Overall, our results showed the superiority of TTEO over LGEO as a feed supplement in broiler diets. In conclusion, TTEO treatment offers a better solution for raising broiler chickens in high stocking density.

Effect of stocking density on performance, meat quality and cecal bacterial communities of yellow feather broilers

Totally, 315 42-day-old male Xueshan chickens were allocated into 3 caging densities, 14, 21 and 28 birds/m². Each treatment was represented by 5 replicates. The body weight (BW), slaughter performance, meat quality, behavioral assessment, and the cecal microorganisms were detected at the market age. The results showed that the BW of broilers in the low- and medium-density groups was significantly higher (p < 0.05) than that of the high-density group from the age of 10 weeks. Only the feather quality of the broilers in the low-density group improved significantly (p < 0.05) compared with those of the other two groups. And, the abdominal fat percentage and the fat content of thigh muscle of broilers in the low- and medium-density groups were higher (p < 0.05) than those in the high-density group. No significant difference (p > 0.05) was noted in the other traits. The abundance of some microbial like Akkermansiaceae, Lactobacillaceae and Faecalibacterium may be correlated with the BW and fat content of broilers. The findings of this study suggest that increasing the stocking density decreased the final BW, fat content and the feather quality, whereas no evidence was found that stocking density caused changes in other parameters.

Role of dietary gamma-aminobutyric acid in broiler chickens raised under high stocking density

The present study was conducted to evaluate the effects of dietary gamma-aminobutyric acid (GABA) in broiler chickens raised in high stocking density (HSD) on performance and physiological responses. A total of 900 male broiler chicks (Ross 308) at 1 d old were assigned in a 2 × 2 factorial arrangement to 4 treatments (10 replicates per treatment) with stocking density, 7.5 birds/m² (low stocking density; LSD) or 15 birds/m² (HSD), and dietary GABA, 0 or 100 mg/kg. Chickens raised in HSD exhibited a decrease in body weight gain in all phases (P < 0.05) and feed intake in starter and whole phases (P < 0.01), and an increase in feed conversion ratio in the finisher phase (P < 0.01) compared with LSD-raised chickens. However, dietary GABA did not affect growth performance nor interacted with stocking density on production variables. The HSD vs. LSD increased relative liver weight on d 35 whereas dietary GABA increased relative liver weight and decreased relative bursa weight on d 21. Both stocking density and dietary GABA affected yield and quality of breast and leg muscles. Dietary GABA increased (P < 0.05) width of tibia on d 35 and interacted (P = 0.054) with stocking density on breaking stocking density on d 35. The HSD vs. LSD group lowered (P < 0.05) feather coverage scores. Significant interaction between stocking density and GABA on surface temperature of shank on d 21 was noted (P = 0.024). Dietary GABA exhibited an opposite effect on the concentrations of cecal short-chain fatty acids depending on stocking density leading to a moderate to significant interaction. Stocking density decreased alpha-1-acid glycoprotein whereas dietary GABA decreased heterophil-to-lymphocyte ratio and corticosterone in blood or serum samples. Serum biochemical parameters were altered by stocking density or dietary GABA. It is concluded that dietary GABA alleviated stress indices including corticosterone and heterophil-to-lymphocyte ratio, but failed to reverse stocking density-induced growth depression.

Supplemental methionine and stocking density affect antioxidant status, fatty acid profiles, and growth performance of broiler chickens

Broilers stocked in high densities may be prone to oxidative and inflammatory insults, resulting in impaired health status, growth performance, and meat quality. This study was to determine if 30% extra supplemental dl-methionine alleviated or prevented those adverse effects of a higher stocking density in broiler chickens. A total of 560 male Cornish Cross cockerels (day old) were divided into four groups: two stocking densities (9 and 12 birds/m2) and two supplementations of methionine (grower: 2.90 or 3.77 g/kg and finisher: 2.60 or 3.38 g/kg). Growth performance was recorded weekly. Blood and tissues were sampled at the end of each period. High stocking density decreased (P < 0.05) body weight and growth performance of growers and (or) finishers. Those differences were partially attenuated by the extra methionine supplementation. The high methionine elevated (P < 0.05) glutathione (GSH) concentration in the thigh at both ages (> 24%). The high stocking density elevated (>28%, P < 0.05) glutathione concentration in the plasma, breast, and thigh of growers, but decreased (P < 0.05) it in the liver of growers and thigh of finishers. Interaction effects (P < 0.05) between dietary methionine and stocking density were found on activities of the antioxidant enzyme glutathione S-transferase in the liver of growers and breast, thigh, and adipose tissue of finishers. The interaction effect was also found on activities of glutathione peroxidase and superoxide dismutase in the thigh of growers. The extra methionine decreased (P < 0.05) hepatic gene expression of heat shock protein 90 (18%) and thigh and breast malondialdehyde concentrations of the finishers (35%). In conclusion, the 30% extra dl-methionine supplementation was able to partially mitigate adverse effects caused by the higher stocking density and to improve the redox status of the broilers.

Assessment of Stocking Rate and Housing System on Performance, Carcass Traits, Blood Indices, and Meat Quality of French Pekin Ducks

Commercial practice in poultry production management has been susceptible to increased problems, driven by concerns about safety of food and animal welfare. Thus, the main proposal of the present study was to evaluate the influence of different stocking densities on performance, blood, and carcass traits of Pekin ducklings reared on two different floor types (wood shaving litter, WSL or plastic slatted floor, PLS). A total of 450 one-day-old ducklings were randomly allocated into six equal experimental groups stocking density (nine, 15 and 21 birds/m2 during the first 14 d and three, five and seven birds/m2 until 49 days) reared on two floor types (WSL and PLS), five replicate pens each. Increased stocking density reduced body weight (BW), weight gain (WG), and feed conversion ratio (FCR) values and increased feed intake (FI) in both floor types at 14 days old. At 49 days old, reared ducklings on PLS type verified higher BW and WG and reduced FCR values. Moreover, increasing stocking density in both floor types significantly reduced the breast, thigh, and left fillet percentages. Conversely, reared birds floored on PLS system decreased the triglycerides (TG) and increased the total cholesterol (TC) serum content. Furthermore, the meat contents of TG and TC were decreased in birds reared on higher stocking density but not affected by floor type. Further, serum antioxidant indices were reduced in PLS birds on low stocking densities. In conclusion, housing Pekin ducklings on PLS improved their growth performance, carcass traits, meat cholesterol, and antioxidant status, particularly at stocking density of three and five birds/m2.

Differences in performance, body conformation, and welfare of conventional and slow-growing broiler chickens raised at 2 stocking densities

Consumer concern for broiler welfare has increased interest in chicken from slower growing (SG) broiler strains. Broilers from SG strains take longer to reach market weight, which may necessitate differences in management practices, such as stocking density. This study evaluated the effects of 2 stocking densities on production performance, body conformation, and welfare of broilers from 2 strains. Broilers from strains that reach market weight at age 42 D (CONV; N = 284) and at 63 D (SG; N = 284) were exclusively stocked into pens at a density of either 29 kg/m² or 37 kg/m². Birds were provided the same starter, grower, and finisher diets with diet phase changes occurring when SG bird body weight (BW) matched CONV. Live BW, body length, pelvic width, shank length, shank width, keel length, breast width, and breast depth were collected at 4 phases: Phase 1—chick placement, Phase 2—starter, Phase 3—grower, and Phase 4—finisher. At Phase 4, footpad dermatitis (FPD), hock burn (HB), and toe damage (TD) were scored. Feed conversion ratio (FCR) and mortality for each pen were recorded throughout the study. Final BW was similar (2.68 kg) for both strains and stocking densities of birds (P > 0.05). CONV bird FCR was 35% more efficient than SG (P < 0.0001). CONV birds had shorter bodies and shanks compared with SG birds at Phases 3 and 4 (P < 0.05). Slower growing birds stocked at 37 kg/m² had the longest bodies and keel bones at Phase 4 (P < 0.01). Also at Phase 4, SG birds stocked at 29 kg/m² had the lowest prevalence of HB (4%), yet the highest prevalence of TD (28%; P < 0.01). These results indicate differences in the effects of strain and stocking density on male broiler conformation, performance, and welfare and highlight the importance of tailoring management practices to the strain of broiler raised.

Research Note: Effects of the rearing method and stocking density on carcass traits and proximate composition of meat in small-sized meat ducks

The present study was conducted to evaluate the effects of different rearing methods and stocking densities on carcass yield and proximate composition of meat in small-sized meat ducks. A total of 555 one-day-old birds were randomly allocated to six treatment groups (three replicates per treatment, sex ratio 1/1) with a 2 × 3 factorial arrangement of two rearing methods (reared in cage or net) and three stocking densities (5 [low], 7 [medium], or 9 [high] birds/m²) until day 70. Five male and five female birds from each replicate were randomly selected and processed to determine the carcass yield. Proximate composition was determined by proximate analysis using the breast and thigh muscles. There was no interaction effect between the rearing method and stocking density on carcass yield. The rearing method affected the thigh muscle rate, which was higher in the cage groups (P < 0.05). The final BW and abdominal fat rate decreased with increasing density (P < 0.05), whereas the thigh muscle rate increased (P < 0.05). There were significant interaction effects (P < 0.05) between the rearing method and stocking density on the content of protein, fat, and collagen. The content of fat and moisture was greater and lower, respectively, in the cage groups (P < 0.05). The content of moisture, fat, and collagen with a medium density was higher (P < 0.05). In addition, the content of protein and fat was lower in the ducks fed in nets at low and high densities (P < 0.05), respectively; the collagen content of breast and thigh muscle was lower in the ducks fed in cages and nets, respectively, at a low density (P < 0.05). Our findings provide valuable insights into the single and interactive effects of the rearing method and stocking density on duck slaughter performance and proximate composition of meat. The results indicate that a rearing system with a cage pattern and a medium density is better than other arrangements for small-sized meat ducks.

Natural immunity in conventionally and organically reared turkeys and its relation with antimicrobial resistance

Suboptimal animal welfare may affect natural immunity, rendering animals more susceptible to environmentally conditioned diseases, including those requiring antimicrobial treatment, which may promote antimicrobial resistance (AMR) in bacterial populations. Herewith, we tested the hypothesis that conventionally raised turkeys have higher levels of AMR in indicator Escherichia coli bacteria, but lower levels of natural immunity, as compared to turkeys reared under organic conditions. Litter and serum samples were collected from 28 conventional and 4 organic turkey farms: E. coli isolates from litter were tested for resistance to 14 antimicrobials, while 3 parameters of natural immunity (i.e., lysozyme, hemolytic complement levels, and serum bactericidal activity) were assessed in the sera. Resistant E. coli isolates were identified in both conventional and organic farms but generally more frequently in conventional farms. High rates of resistance to ampicillin (96%), tetracycline (95%), streptomycin (82%), sulfamethoxazole (80%), ciprofloxacin (73%), and trimethoprim (71%), as well as high rates of multiresistance, were observed in conventional farms. Organically raised turkeys had significantly higher levels of lysozyme and serum bactericidal activity than conventional turkeys, and these levels were also higher in turkeys housed in farms where AMR frequency was lower. Findings support the hypothesis that conventional farming conditions may affect turkeys' natural immunity, rendering the animals more susceptible to environmentally conditioned diseases requiring antimicrobial treatment, which would in turn promote AMR. Reducing AMR in turkey farming is therefore more likely to be successful when considering animal welfare as an option to reduce the need of antimicrobial use.

Effects of Cassia abbreviata extract and stocking density on growth performance, oxidative stress and liver function of indigenous chickens

The objective of the study was to investigate the effect of stocking density and extract from Cassia abbreviata stem bark on growth performance, oxidative stress and liver function of indigenous chickens. A total of 420 1-day-old female Ovambo chicks with initial body weight of 0.32 ± 0.036 kg (mean ± SD) were used in the study. Birds, which were cooped in stocking densities consisting 5, 10 and 20 birds/m², were orally administered with 0, 50, 200 and 500 mg/kg of extract from C. abbreviata stem bark. Each stocking density per dosage level of extract was repeated three times. Average feed intake was lower (P < 0.05) in birds housed at 20 birds/m². There was a low (P < 0.05) average daily gain in birds housed at 20 birds/m². Malondialdehyde was higher (P < 0.05) in 20 birds/m². Average daily gain was high (P < 0.05) in birds administered with 0 and 50 mg/kg of C. abbreviata stem bark extract. Birds administered with 0 and 50 mg/kg of C. abbreviata stem bark extract had a higher (P < 0.05) gain to feed ratio. Birds dosed with 500 and 200 mg/kg had high (P < 0.05) superoxide dismutase activity. Birds administered with 500 mg/kg of C. abbreviata stem bark extract had the lowest (P < 0.05) malondialdehyde. A 500 mg/kg of stem bark extract from C. abbreviata resulted to higher (P < 0.05) activities of aspartate transaminase and alanine transaminase. There was a significant (P < 0.05) interaction between the stocking density and C. abbreviata extract on catalase activity. High stocking density of 20 birds/m² reduced growth performance and induced stress in indigenous chickens. High dosage of level 500 mg/kg of stem bark extract of C. abbreviata reduced oxidative stress while depressing growth performance and causing hepatotoxicity in birds. There is a need to precisely determine the maximum dosage level of C. abbreviata extract to improve growth performance and reduce oxidative stress and hepatotoxicity in indigenous chickens in high stocking density.

The influence of environmental enrichment and stocking density on the plumage and health conditions of laying hen pullets

In this study, the effects of environmental enrichment, stocking density, and microclimate on feather condition, skin injuries, and other health parameters were investigated. During 2 rearing periods (RP), non-beak-trimmed Lohmann Brown hybrid pullets were housed in an aviary system for rearing with cages and from week 5 of age onwards with access to a litter area. All pullets were reared in the same barn and under practical conditions. In total, 9,187 (RP 1) and 9,090 (RP 2) pullets were distributed in 9 units, and each unit was assigned to 1 of 3 experimental groups (EG). In the control group (EG 1), the pullets were kept without environmental enrichment and at a commonly used stocking density (22 to 23 pullets per m²). Each unit of the 2 treatment groups was provided with 3 types of environmental enrichment simultaneously (pecking stones, pecking blocks, and lucerne bales), and the pullets were kept at a lower than usual (18 pullets per m²) (EG 2) or commonly used stocking density (EG 3). In each RP, the plumage condition, injuries and health of the pullets, and the microclimate of the housing system were examined 5 times. The statistical relationships of enrichment, stocking density, and microclimate with animal health were estimated via regression models. We found that the provision of environmental enrichment had a significant increasing effect on the plumage quality in week 17. Furthermore, significant relationships were found between several predictors (temperature in the housing system, dust concentration, and age of the pullets) and response variables (plumage condition, body injuries, head injuries, bodyweight, difference to the target weight and uniformity). The results of this study showed that increasing temperature in the housing system and increasing age of the pullets are significantly associated with the occurrence of feather damage and skin injuries during rearing. With stocking densities as high as we used (all > 17 pullets per m²), no significant positive effect of a reduced stocking density could be observed.

Effect of stocking density and alpha-lipoic acid on the growth performance, physiological and oxidative stress and immune response of broilers

Objective

The study was conducted to evaluate the effect of stocking density and alpha-lipoic acid (ALA) on the growth performance, feed utilization, carcass traits, antioxidative ability and immune response of broilers.

Methods

A total of 1,530 22-day-old male broilers (Arbor Acres) with comparable body weights (731.92±5.26) were placed into 18 cages (2.46×2.02 m) in groups of 75 birds (15 birds/m², 37.5 kg/m²; low stocking density [LD]), 90 birds (18 birds/m², 45.0 kg/m²; high stocking density [HD]) and 90 birds with 300 mg/kg ALA added to the basal diet (18 birds/m², 45.0 kg/m²; HD+ALA, high stocking density+α-lipoic acid); each treatment was represented by 6 replicates. The experimental period was 3 weeks.

Results

The results showed that the high stocking density regimen resulted in a decreased growth, feed conversion ratio, carcass weight, thigh yield and bursa weight relative to body weight (p<0.05) on d 42. The abdominal fat yield in the HD+ALA group was lower (p = 0.031) than that of the LD group at 42 d. The superoxide dismutase and glutathione peroxidase activities in serum were increased, and malondialdehyde content decreased after adding ALA product (p<0.05) on d 42. Additionally, the serum concentrations of immunoglobulin A (IgA) and IgG were decreased (p<0.05) and the level of diamine oxidase was higher (p< 0.01) in the HD group on d 42.

Conclusion

The high stocking density significantly decreased broiler growth performance, feed utilization and carcass traits, increased physiological and oxidative stress and induced intestinal mucosal injury. The supplementation of ALA product in broiler diet at 300 mg/kg may reduce the adverse effects of high stocking density-mediated stress by maintaining the antioxidant system and humoral immune system.

The potential of the transect method for early detection of welfare problems in broiler chickens

The potential of the transect method was tested for early detection of welfare problems associated with bird age and genetic line, litter quality, and transect location. On-farm welfare impairment and its consequences on slaughter outcomes were evaluated to test the method's predictive ability. A total of 31 commercial Ross, Cobb, and mixed RC broiler flocks were evaluated at 3, 5, and 6 wk of age. Two observers evaluated 3 transects each, simultaneously and in the same house by detecting welfare indicators including lame, immobile, sick, small, dirty, tail wounds, other wounds (head and back wounds), featherless, terminally ill, and dead birds. Increasing lame, immobile, sick, and terminally ill birds according to bird age (P < 0.001) was detected. Higher incidences of small and sick birds were detected in C and RC (P < 0.001) as compared to R flocks, whereas more dead and tail wounded were observed in RC compared to R and C flocks at week 5 (P < 0.001). Dirty incidence increased as litter quality deteriorated (P < 0.001). A higher incidence of immobile, small, sick, dirty, and dead was registered near house walls (P < 0.001). Differences across observers were detected for lame, immobile, and terminally ill birds (P < 0.001). For the observer by bird age interaction, differences were detected for dirty, tail wounds, and other wounds (P < 0.05). Pearson correlations between welfare indicators at week 3 and those at final weeks of age (P < 0.05) ranged between r values of -0.2 and 0.654 (P < 0.05). Correlations between welfare indicators and slaughter outcomes showed a relationship between flock mortality and dead on arrival, footpad dermatitis, leg problems, and illness (P < 0.05). Litter quality positively correlated with downgrades (P < 0.001). This study showed the potential of transects to detect differences in welfare indicators according to factors that effects were previously reported. It demonstrated the transect potential for detecting and predicting the consequences of welfare impairment on slaughter outcomes. This would make the transect method a useful tool for notifying and rectifying welfare deterioration as early as at 3 wk of age.

Effects of reduced-protein diets supplemented with protease in broiler chickens under high stocking density

The effects of protease supplementation on productive performance and physiological responses were investigated in broiler chickens fed reduced crude-protein (low-CP) diets and reared under normal or high stocking densities (SD). Chicks were housed in pens with two stocking densities (≈10 birds/m2 or ≈15 birds/m2) and fed diets with either the recommended or reduced level of CP and metabolisable energy (ME) from 1 to 21 days. From 22 to 42 days, an equal number of birds from each dietary group was fed one of the following finisher diets: (1) recommended-CP and ME, (2) low-CP and recommended-ME or (3) low-CP and recommended-ME supplemented with protease. No interactions (P &gt; 0.05) were observed between diet and SD for feed intake (FI), weight gain (WG), feed conversion ratio (FCR), Newcastle disease antibody titre, pododermatitis, caecal clostridia, Escherichia coli, lactobacilli, serum corticosterone or acute-phase proteins. Diet had no effect (P &gt; 0.05) on FI, WG or FCR during the finisher period nor on FI and WG during the overall (1–42 days) period. High SD resulted in lower FI (P &lt; 0.05) and Newcastle disease antibody titre (P &lt; 0.05) and higher FCR (P &lt; 0.05), pododermatitis incidence (P &lt; 0.05), caecal population of clostridia (P &lt; 0.05) and E. Coli (P &lt; 0.05), and acute-phase protein and corticosterone concentrations than did normal SD. In conclusion, the supplementation of protease to a low-CP diet during the finisher period had no effect on the performance and immunity of overcrowded broiler chickens. Regardless of dietary CP and protease supplementation, a high SD negatively affected the growth performance, immunity, caecal microflora and welfare of the broiler chickens.

Effect of stocking density on behavioral traits, blood biochemical parameters and immune responses in meat ducks exposed to heat stress

High stocking density (HSD) and heat stress (HS) caused by climate change can lower blood homeostasis and negatively impact the behavioral traits of animals. The objective of this study was to explore the influence of stocking densities on behavioral traits, blood parameters, immune responses, and stress hormones in meat ducks (Cherry valley, Anas platyrhynchos) exposed to HS. A total of 320 meat ducks were assigned to four groups with different stocking densities using a randomized complete block design. The ducks were then reared for 42 days. The assigned density groups were as follows: (1) control group (CON, three birds m- 2 , normal environmental heat conditions); (2) low stocking density (LSD, three birds m- 2 , heat stress conditions); (3) medium stocking density (MSD, four birds m- 2 , heat stress conditions); and (4) high stocking density (HSD, six birds m- 2 , heat stress conditions). To induce HS, the environment of the poultry house was set to a temperature of 34 ± 2 ∘ C with a relative humidity of 70 % from 11:00 to 16:00 for the finisher period (from day 22 to day 42 of the rearing period). Concentrations of blood triacylglycerol, total cholesterol, low-density lipoprotein cholesterol (LDL-C), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) were higher in the HS groups compared with the CON group, with HSD showing the highest levels ( P < 0.05 ). The concentrations of high-density lipoprotein cholesterol (HDL-C) and glucose were lower in the HSD groups than in the CON group ( P < 0.05 ). Red blood cell (RBC) and platelet (PLT) counts were lower in HS groups compared with the CON group, with the HSD group displaying the lowest counts ( P < 0.05 ). Blood pH values were also higher in the HS groups than in the CON group, with the highest values observed in the HSD group ( P < 0.05 ). Concentrations of blood p CO 2 ,HCO 3 , and T CO 2 were higher in the HS groups than in the CON group, with HSD showing the lowest levels ( P < 0.05 ). The concentration ofPO 2 was higher in CON than in any of the HS groups, with the lowest levels found in the HSD group ( P < 0.05 ). The concentrations of blood IgG and corticosterone were increased in the HS groups compared with the CON group ( P < 0.05 ). Animal behavioral trait scores were also higher in HS groups than in the CON group ( P < 0.05 ); these scores were the highest in the HSD group. Overall, animal behavioral traits, blood biochemical parameters, and immune responses in meat ducks exposed to heat stress were highest in the HSD group, but not significantly different between the LSD or MSD groups.

Reducing Stress Susceptibility of Broiler Chickens by Supplementing a Yeast Fermentation Product in the Feed or Drinking Water

Reducing stress is an important goal in animal production. Previous research has demonstrated the ability of Original XPC^TM to reduce the stress response of broilers during heat stress. Three trials were conducted to evaluate the effects of adding Original XPC^TM to the feed or AviCare^TM to the water on stress susceptibility of broiler chickens. Treatments included: control nonstressed (CNS), control stressed (CS), stressed with Original XPC^TM (1.25 kg/metric ton feed, 0⁻42 days; XPC), and stressed with AviCare^TM (160 mL/100 L drinking water, 0⁻42 days; AVI). All stressed treatments received the following stressors: live coccidiosis vaccination (day 1), reared on reused litter (days 0⁻42), and heat stress with feed/water withdrawal (12 h on day 18). Plasma corticosterone and heterophil/lymphocyte (H/L) ratio were determined from 60 birds/T on day 19, and 24 birds/T on day 41. Physical asymmetry was determined using bilateral bone measurements from 60 birds/T on day 41. Birds provided XPC or AVI had lower corticosterone and H/L ratios than CS (p < 0.05) on day 19 and lower corticosterone, H/L ratios, and asymmetry scores than both CNS and CS on day 41 (p < 0.05) in all three trials. Supplementing XPC or AVI improved broiler welfare measured by reduced stress indicators after acute heat stress or normal rearing stress in all trials.

Assessing the Effects of Stocking Density on Turkey Tom Health and Welfare to 16 Weeks of Age

Four levels of turkey tom stocking density (SD) (30, 40, 50, 60 kg/m2) were evaluated in two 16 week trials (n = 2,868 Nicholas Select). Poults were allocated to one of eight independently ventilated rooms per trial (6.71 × 10.06 m) based on final predicted body weight (two replicates per SD per trial). Room temperature, humidity, carbon dioxide and ammonia concentration were recorded throughout the trial; ventilation was adjusted to equalize air quality across treatments. Mobility (gait score, scale 0-5) was recorded at 12 and 16 weeks (20 birds per replicate). Footpad lesion score (scale 0-4), feather condition (scale 1-4), and cleanliness scores (scale 1-4) were recorded at 10 (Trial 2), 12, and 16 weeks of age (20 birds per replicate). Aggressive injury incidence was recorded daily for Trial 2. Stress (heterophil/lymphocyte ratio) was evaluated at 4, 12, and 16 weeks of age (15 birds per replicate). Behavior was recorded and scan sampled (field of view) at 12 (Trial 1), 14, and 16 weeks. Data were analyzed using regression analysis (linear, Proc Reg; quadratic, Proc RSReg) for relationships between the variables and SD. Differences were considered significant when p ≤ 0.05. Mobility and footpad lesions were negatively affected by increasing SD (linear) at 16 weeks only. Feather condition and cleanliness decreased linearly as SD increased at week 10, 12, and 16. The incidence of aggressive damage was higher as SD increased during week 4-8 (quadratic). Heterophil/lymphocyte ratios increased linearly at 4 weeks (similar trend at 12 weeks). Behavior was impacted at 12 weeks of age with standing behavior showing a quadratic response, and walking and total disturbance showing a linear decrease as SD increased. Resting, preening, and comfort behaviors increased linearly (14 weeks), while walking and strutting decreased linearly with increasing SD. Finally, at 16 weeks of age resting, standing, walking, feeding, and total disturbance responded quadratically while preening behavior increased linearly with increasing SD. Results suggest that increasing SD negatively impacts bird health and wellbeing through decreased mobility, increased footpad lesions, poorer feather condition and cleanliness, and behavioral changes, but that very low SD (30 kg/m2) may result in increased aggressive damage.

Effect of stocking density vis-à-vis dietary protein supply on growth performance, immune-competence and cost economics of growing turkey poults

A 10-week biological experiment was undertaken to evaluate the response of Beltsvilie Small White turkey poults to different floor space (0.6, 0.8, and 1.0 ft2/bird) and dietary protein levels (22%, 24% and 26% with similar dietary energy) in terms of growth performance, immune response, and serum biochemistry, following 3 × 3 factorial design. Each treatment was allocated 4 replicates out of which one replicate was maintained for the replacement of the dead birds, if any, to maintain the required stocking density. The body weight gain (BWG), feed intake (FI) and performance index (PI) of poults was significantly higher in 1.0 ft2 floor space during 0–4 weeks and 4–10 weeks of age. Similarly, higher BWG, FI, and PI were observed at 26% dietary protein level. The interaction effect between stocking density and protein levels during 0–4 week resulted in significantly higher FI at 0.8 ft2 floor space with 26% protein level and 1.0 ft2 floor space with 24% as well as 26% protein level. The feed conversion ratio (FCR), mortality pattern, immune response and immune organ weights of poults did not reveal any significant treatment effect. The feed cost/bird increased linearly with increasing floor space, and feed cost/kg weight gain and feed cost/ kg meat increased linearly with increasing protein levels. However, profit potential per meter square decreased linearly with decreasing stocking density. The study concluded that increasing the stocking density and decreasing the dietary protein level decrease the performance of poults, but the profit potential per meter square increases with increasing stocking density. Thus, the study recommends either the floor space of 0.8 ft2/bird with 26% dietary protein level or the floor space of 1.0 sq2/bird with 24% dietary protein level for growing turkey poults.

Associations among gait score, production data, abattoir registrations, and postmortem tibia measurements in broiler chickens

Lameness and impaired walking ability in rapidly growing meat-type broiler chickens are major welfare issues that cause economic losses. This study analyzed the prevalence of impaired walking and its associations with production data, abattoir registrations, and postmortem tibia measurements in Norwegian broiler chickens. Gait score (GS) was used to assess walking ability in 59 different commercial broiler flocks (Ross 308) close to the slaughter d, 5,900 broilers in total, in 3 different geographical regions. In each flock, 100 arbitrary broilers were gait scored and 10 random broilers were culled to harvest tibias. Abattoir registrations on flock level were collected after slaughter. A total of 24.6% of the broilers had moderate to severe gait impairment. The broilers were sampled in 2 stages, first slaughterhouse/region, and then owner/flock. The final models showed that impaired gait is associated with first-week mortality (P < 0.05), region (P < 0.001), height of tibias mid-shaft (P < 0.05), and calcium content in the tibia ash (P < 0.05), and negatively associated with DOA (P < 0.05). The prevalence of impaired gait indicates that this is a common problem in the broiler industry in Norway, although the mean slaughter age is only 31 d and the maximum allowed animal density is relatively low. Impaired walking ability could not be predicted by the welfare indicators footpad lesion score, total on-farm mortality, and decreasing DOA prevalence. Further studies are needed to explore the relationship between first-week mortality and gait score.

Performance study of White Pekin ducks in different stocking density in floor rearing system

To study the effect of different stocking density on the performance of White Pekin ducks, 144 unsexed day-old White Pekin ducklings were reared for 42 days and on 43rd day, these duckings were distributed into four equal groups, each with three replicates in deep litter system of rearing. The floor space provided per ducking was G1 : 1,350 cm2, G2 : 1,800 cm2 , G3 : 2,250 cm2 and G4 : 2,700 cm2. The experiment continued from 7-10th weeks of age. The parameters studied were body weight, body weight gain, feed consumption, feed conversion ratio (FCR), serum biochemical profile, carcass characteristics and litter moisture content. The 7th and 8th week body weight gain of all the treated groups did not differ significantly but higher body weight of ducks were recorded in G3 and G4 groups than that of G1 and G2 groups at 9th and 10th week of age. The cumulative (7-10 weeks) body weight gain and FCR of white Pekin ducks was higher in group G3 and G4 than that of G1 and G2 groups. Cumulative feed consumption of all the treated groups of ducks did not differ significantly. No significant difference was observed in the studied serum biochemical and carcass characteristics of the treated groups. The litter moisture content was lower in G3 and G4 than that of G1 and G2 groups in all the studied periods. From this, it may be concluded that the floor space of 1,350 cm2 up to 8th week and 2,250 cm2 at 9th and 10th weeks of age per Pekin duck is suitable with respect to production performance of birds.

Effect of Different Flooring Designs on the Performance and Foot Pad Health in Broilers and Turkeys

Simple Summary

The contact of the birds’ feet with litter and their excreta during the fattening period might lead to reduced body weight, carcass weight, feed intake, and impaired foot pad health in poultry. This study was performed to evaluate the influence of different flooring designs with reduced (50% or 100% slatted floors) contact to the excreta on the above-mentioned parameters in the fattening of broilers and turkeys. The provision of litter on the floor had no relevant effect on foot pad health in broilers. Using fully-slatted flooring in fattening turkeys led to a higher body weight, while reducing incidence of injuries of foot pads. It is, therefore, necessary to consider how a similar excellent litter quality can be achieved in basically littered husbandry systems common in Europe.

Abstract

Litter quality has a significant influence on the performance and foot pad health in poultry. The objective of this study was to evaluate the effects of different types of flooring designs on the performance and foot pad health in fattening broilers and turkeys. Three trials were conducted for each species using a total of 720 Ross 308 broilers and 720 Big 6 turkeys. After day seven, animals were randomly assigned to four groups with three subgroups each: G1—floor pens with litter, G2—floor pens with litter and floor heating, G3—partially-slatted flooring, including a littered area, and G4—fully-slatted flooring with a sand bath (900 cm²). Animals of both species had a significantly higher final body weight at dissection (day 36) after being reared on fully-slatted floors compared to common littered floors. In turkeys, the feed conversion ratio was worse in G4 (1.53 ± 0.04) than in G1 (1.47 ± 0.02) and G2 (1.48 ± 0.03). Water to feed ratio was significantly higher in G2 than other groups. Turkeys’ foot pad health was significantly better in G4 than in other groups beginning at day 21. In turkeys, platforms with slatted floors that allow for temporary separation of the feet from the litter could lead to improvements in foot pad health which could better enable the realization of species-specific behaviours and activities in littered areas.

Effects of stocking density on growth performance, meat quality and tibia development of Pekin ducks

This study was performed to investigate the effects of stocking density on performance, meat quality and tibia development in Pekin ducks reared on a plastic wire floor. A total of 372 healthy, 21-day-old, male ducks with similar body weight (BW) were randomly allotted to stocking densities of five (low), eight (medium) and 11 (high) birds/m² . Each group had six replicates. Results showed that compared with the low density group, medium and high stocking density caused a decrease in final BW at 42 days old, and in average daily gain, European performance index (p < .01) and meat pH at 45 min postmortem (p < .001), and an increase of meat drip loss (p < .01). High stocking density resulted in an increase of feed/gain ratio (p < .001), but a decrease of tibia calcium (p < .01) and phosphorus content (p < .05). Meat color, shear force values, tibia size (weight, length, and width) and breaking strength were not significantly influenced by stocking density. In conclusion, stocking density over eight birds/m² negatively affects growth performance, but meat quality and tibia development are not dramatically influenced. Based on this study, the stocking density of male Pekin ducks should be adjusted between five and eight birds/m² .

Comparisons of management practices and farm design on Australian commercial layer and meat chicken farms: Cage, barn and free range

There are few published studies describing the unique management practices, farm design and housing characteristics of commercial meat chicken and layer farms in Australia. In particular, there has been a large expansion of free range poultry production in Australia in recent years, but limited information about this enterprise exists. This study aimed to describe features of Australian commercial chicken farms, with particular interest in free range farms, by conducting on-farm interviews of 25 free range layer farms, nine cage layer farms, nine barn layer farms, six free range meat chicken farms and 15 barn meat chicken farms in the Sydney basin bioregion and South East Queensland. Comparisons between the different enterprises (cage, barn and free range) were explored, including stocking densities, depopulation procedures, environmental control methods and sources of information for farmers. Additional information collected for free range farms include range size, range characteristics and range access. The median number of chickens per shed was greatest in free range meat chicken farms (31,058), followed by barn meat chicken (20,817), free range layer (10,713), barn layer (9,300) and cage layer farms (9,000). Sheds had cooling pads and tunnel ventilation in just over half of both barn and free range meat chicken farms (53%, n = 8) and was least common in free range layer farms (16%, n = 4). Range access in free range meat chicken farms was from sunrise to dark in the majority (93%, n = 14) of free range meat chicken farms. Over half of free range layer farms (56%, n = 14) granted range access at a set time each morning; most commonly between 9:00 to 10.00am (86%, n = 12), and chickens were placed back inside sheds when it was dusk.

ANIMAL BEHAVIOR AND WELL-BEING SYMPOSIUM: Poultry welfare assessments: Current use and limitations

Recent attention has been given to developing welfare assessment tools for research purposes and for use directly on poultry farms. Historically, most of these tools have relied on resource- and management-based measures, but it is unclear how well they correlate with outcomes indicative of positive animal welfare. The subjective nature of many of these tools also makes it difficult to generalize across studies and farms without extensive training. More recently, the European Union Welfare Quality project set out to design assessment tools that were scientifically based and combined resource- and management-based measures with animal-based measures. Adding these measures was especially important for farm-level comparisons where farms may be utilizing different housing systems with inherent differences affecting the utility of resource- and management-based measures. The Welfare Quality Assessment protocol for poultry (WQA) offers researchers a tool that has been validated, tested for repeatability, and standardized across farms. This tool has been used in the United States and Canada at both the experimental and farm levels. The WQA is continuing to be developed, but many measures are still in need of validation and benchmarking as well as creating measures that can be used without needing extensive training to be successful on a go-forward basis. Tools must be designed for North American commercial production with a better understanding of the appropriate sample size, as well as their utility for use in alternative and extensive housing systems. The WQA shows promise in helping us to understand the influence of genetics, housing design, and management factors on the welfare of poultry.

Influence of probiotic supplementation on immune response in broilers raised under hot climate

1. The objective of the study was to evaluate the potential effects of dietary probiotic supplementation and stocking density and their interaction on growth performance, humoral and cellular immune responses of broiler chickens raised under hot climate conditions. 2. A total of 1800 1-d-old unsexed broiler chicks (Ross 308) were allocated in a completely randomised 3 × 2 factorial design, with three concentrations of dietary probiotic (0, 200 and 400 mg/kg) containing 4 × 10⁹ cfu/g of Bacillus subtilis and two stocking densities (12 or 18 birds/m²) in a total of 6 treatment subgroups. 3. Dietary probiotic and stocking density had no significant effect on live body weight, feed consumption and feed conversion ratio. 4. Dietary probiotic supplementation had a positive effect on serum immunoglobulin M (IgM) and cell-mediated immunity when compared to the control at 6 weeks of age, whereas serum immunoglobulin A (IgA) and immunoglobulin Y (IgY) were improved, but not significantly so. Dietary probiotic and stocking density had no effect on relative weights of the bursa of Fabricius and spleen. 5. Dietary probiotic supplementation had a positive significant effect on serum IgM concentration and cell-mediated immunity without penalising growth performance in broilers raised under high ambient temperature.

Effect of litter quality on foot pad dermatitis, hock burns and breast blisters in broiler breeders during the production period

Foot pad dermatitis and hock burn lesions are a form of contact dermatitis, a condition affecting skin areas in contact with unsuitable or irritating material. Contact dermatitis is a common problem, reducing the welfare of broilers, and is believed to also affect broiler breeders. However, there is very little research on contact dermatitis in breeders. This study followed the severity of foot pad lesions in broiler breeders throughout the production period. At slaughter the presence of hock burns and breast blisters was also determined. In addition, changes in litter condition over time and the impact of litter quality on foot pads were evaluated. The study was performed on 10 broiler breeder farms, including altogether 18 flocks. Foot pads of 100 hens per flock were assessed at the end of rearing period, three times during the production period, and at slaughter. Foot pad and hock lesions, as well as litter condition were scored on a 5-point scale. Litter quality was evaluated as pH, moisture and ammonia content. The condition of foot pads deteriorated towards slaughter age, with the occurrence of severe lesions reaching a maximum of 64% on average at slaughter. Hock lesions and breast blisters were rare. The litter layer became drier over time. Although poorer litter condition and wetness influenced foot pad health negatively, the effect on severe lesions was not significant. We also observed a negative effect on foot pad condition of larger slat areas. In conclusion, maintaining good litter quality alone is not enough to ensure healthy foot pads in broiler breeders.