Effect of Environmental Enrichment on the Behavior and Welfare of Japanese Broilers at a Commercial Farm

Association of Major Histocompatibility Complex Polymorphism With Acute Phase Response in Broiler Chicken

BACKGROUND

Stress associated with changes in host immunity occurs in response to altered environmental conditions, endogenous imbalances, infectious agents and harmful stimuli. The importance of genetic diversity in chickens has increased due to individual immune differences towards resistance and susceptibility to various stimuli.

OBJECTIVES

This study aimed to investigate the association of major histocompatibility complex (MHC) polymorphism with acute phase response (APR) in Ross 308 broiler chickens.

METHODS

The allelic diversity of the LEI0258 microsatellite marker was determined in 120 Ross broilers. In addition, acute phase proteins (APPs), including serum amyloid A (SAA) and alpha-1-acid glycoprotein (AGP), were analysed as markers of the APR. Furthermore, leukocyte count and the heterophil/lymphocyte ratio (H/L ratio) were examined. The antibody response to the Newcastle disease vaccine (NDV) was also measured to assess humoral mediated immunity. Lastly, the correlation between immune responses and MHC alleles was investigated to identify the most effective alleles in a stress-related situation.

RESULTS

A total of six alleles, ranging from 195 to 448 bp, were identified. Association study revealed a significant influence of MHC alleles on APPs in Ross population (p < 0.05). Notably, Allele 448 had a significant correlation with SAA concentration and the H/L ratio. Allele 207 displayed a positive association with AGP concentration, whereas Allele 195 showed a negative association. Furthermore, a significant association was observed between Allele 448 and basopenia, as well as between Allele 195 and monocytosis.

CONCLUSIONS

Results confirmed the significance of MHC as a candidate gene marker for immune responses, which supports its use for vaccine design, genetic improvement of disease-resistant traits and resource conservation in commercial broiler chickens.

Cytokine and acute-phase proteins response following vaccination against infectious bronchitis in broilers

BACKGROUND

Infectious bronchitis (IB) is an important disease of poultry, and vaccination is the best method of preventing IB in the poultry industry worldwide.

OBJECTIVES

This study was designed to evaluate cytokine and acute-phase protein (APP) responses and their correlations with antibody titres following vaccination regimes against IB in the broiler.

MATERIALS AND METHODS

Broilers were vaccinated with H120 and 1/96 vaccine strains, and MIX (H120 + 1/96) vaccine strains on Days 0 and 14. Heterophils/lymphocyte (H/L) ratio, APPs including chicken serum amyloid A (SAA), chicken pentraxin 3 (chPTX3), chicken interleukin 1β (IL-1β), chicken interleukin 6 (IL-6) levels and antibody titres were measured.

RESULTS

An increase in the H/L ratio, SAA, chPTX3, IL-1β and IL-6 levels in vaccinated groups was observed 1 day after the first (highest rates) and second (lower levels) vaccination up to 3 days in three different patterns and then started to decrease. The results showed an immediate, short-lived response and moderate increases in all criteria. Changing patterns of APPs were different but in similar pattern after the first and second immunization in vaccinated groups. A positive correlation between all criteria values on Days 1 and 15 with antibody titres on Day 28 may indicate agonistic cross-regulation.

CONCLUSION

Different types of IB vaccines could induce different patterns of APPs responses, which can be used to evaluate immune response outcomes in vaccine design, development and administration. The IL-6 with the highest increase can be a sensitive parameter and chPTX3 with the high increase could be an important criterion.

Effects of grain-based pecking blocks on productivity and welfare indicators in commercial broiler chickens

OBJECTIVE

This experiment was conducted to investigate the effect of grain-based pecking blocks on productivity and welfare status at two commercial broiler welfare-certified farms.

METHODS

Production and welfare indicators were assessed at two farms (designated Farm A and B). Both farms had two windowless houses with forced tunnel-type ventilation and housed broilers at stocking densities of approximately 16.7 birds/m2 (Farm A) and 16.8 birds/m2 (Farm B). Each house was divided into two or three equal sections and was provided with or without pecking blocks. Grain-based pecking blocks, measuring 25 × 25 × 25 cm, were given to broilers in both farms at 1 block per 1,000 birds. Various parameters including productivity (body weight and flock uniformity), corticosterone levels (in fecal droppings and feathers), footpad dermatitis, hock burn, feather dirtiness, gait score, litter quality, body surface temperature, and volatile fatty acids in fecal samples were assessed at 26 days of age, whereas litter quality was analyzed at 13 and 26 days of age.

RESULTS

There were no significant effects of providing pecking blocks on productivity (body weight and uniformity), fecal and feather corticosterone, welfare indicators (i.e., footpad dermatitis, hock burn, feather cleanliness, and gait score), and litter quality (i.e., moisture, nitrogen, and pH). No differences in body surface temperature between the control and enrichment treatments were noted in Farm B, but body surface temperatures of the head (p = 0.029) and legs (p = 0.011) in the enrichment vs. control group were elevated in Farm A. Butyrate concentration in the enrichment vs control group was higher in Farm B (p = 0.023), but this effect was not detected in Farm A.

CONCLUSION

It is concluded that grain-based pecking blocks did not affect performance and welfare indicators. Further studies are warranted to elucidate the potential impact of grain-based pecking blocks on gut health indicators.

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.

The Influence of Different Types of Environmental Enrichment on the Performance and Welfare of Broiler Chickens and the Possibilities of Real-Time Monitoring via a Farmer-Assistant System

The aim of this study is to evaluate the influence of environmental enrichment on the growth performance, litter and/or air quality as well as animal welfare indicators of broilers. Control groups (CG) and trial groups (TG) were housed under identical conditions during six fattening runs, with the TG having three types of environmental enrichment and a Farmer-Assistant System (FAS). A representative number of 50 birds were weighed and litter samples were taken at d 14, 21 and 28. Additionally, the same broilers were examined for foot pad dermatitis (FPD) on those days. The average bodyweight of the birds in the CG was significantly lower (1671 g) only at d 28 compared to TG (1704 g); at d 14, d 21 and d 33 at the slaughterhouse, no significant differences were observed. The dry matter content in the litter did not significantly differ between CG and TG. Birds housed in CG had significantly higher FPD scores at d 14 (1.24) and d 21 (2.19) compared to those housed in TG (0.73 and 1.52, respectively). No effects on air quality parameters, such as CO2 and NH3, were seen between the groups. Overall, our study shows no negative influences of environmental enrichment on growth performance, litter and air quality.

Positive Effects of Elevated Platforms and Straw Bales on the Welfare of Fast-Growing Broiler Chickens Reared at Two Different Stocking Densities

In conventional rearing systems, fast-growing broiler chickens commonly experience welfare issues, such as contact dermatitis, walking difficulties or a lack of expression of species-specific behaviours. Enriching their environment may be a way to improve their welfare. The objective of this study was to evaluate the benefits of elevated platforms and straw bales on the welfare of fast-growing broiler chickens reared at two different stocking densities. A total of 14,994 Ross 308 broilers were housed in 12 pens according to 4 treatments: 31 kg/m² with or without enrichments and 41 kg/m² with or without enrichments. The broilers' walking ability, footpad dermatitis (FPD), hock burns (HB), weight, mortality and litter quality were assessed. Stocking density had a negative effect on FPD and HB, whereas enrichments reduced the occurrence of FPD and HB at both densities. There was a positive enrichment effect and a negative density effect on body weight at 25 days and on walking ability, but no effect on the litter quality or mortality rate. These results confirm that an enriched environment improves animal welfare in confined chickens, regardless of the stocking density. Reducing stocking density clearly appears to be an important means of increasing animal welfare.

Quercetin Regulates Calcium and Phosphorus Metabolism Through the Wnt Signaling Pathway in Broilers

This study intended to explore the effect and mechanism of different doses of dietary quercetin on calcium and phosphorus metabolism to provide an experimental basis for preventing leg disease in broilers. A total of 480 1-day-old healthy Arbor Acre broilers were randomly allotted into four groups (0, 0.02, 0.04, 0.06%) for 42 days. Compared with control, 0.06% quercetin significantly increased the unit weight and the relative weight of tibia in broilers (P < 0.05). Meanwhile, phosphorus content and bone mineral density (BMD) were significantly increased by 0.06% dietary quercetin supplementation in tibia (P < 0.05). Ash of tibia was significantly increased by 0.04 and 0.06% quercetin in broilers (P < 0.05). In addition, 0.06% quercetin significantly increased the content of serum calcium-binding protein (CB), estradiol (E₂), osteocalcin (OC), alkaline phosphatase (ALP), and calcitonin (CT) (P < 0.05); 0.04% quercetin significantly increased 1,25-dihydroxyvitamin D₃ (1,25-(OH)₂D₃) (P < 0.05) content in serum of broilers. The content of serum parathyroid (PTH) was significantly decreased by 0.02 and 0.06% quercetin (P < 0.05) in broilers. Gene Ontology (GO) functional annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that the Wnt signaling pathway was a key signaling pathway of calcium and phosphorus metabolism in broilers which was significantly regulated by quercetin. The differentially expressed genes (DEGs) from transcriptome sequencing were validated with real-time quantitative PCR (RT-qPCR). In conclusion, 0.06% dietary quercetin supplementation improved calcium and phosphorus metabolism by regulating the Wnt signaling pathway in broilers.

The modulatory effect of carvacrol on viral shedding titer and acute phase response in broiler chickens experimentally infected with infectious bronchitis virus

Infectious bronchitis virus (IBV) is one of the major respiratory diseases of broiler causing huge economic losses. The inability to control IBV using different vaccination programs owing to the high mutation rate and recombination ability of the RNA genome generates IBV variants. This study was designed to give a specific perspective of carvacrol effect on early immune response, viral shedding titer, oxidative stress, serum biochemical parameters and clinical consequences in broilers experimentally infected by IBV. One hundred and twenty-one-day old commercial broiler chicks were equally divided into 4 groups. First group was considered as control. Second group was given carvacrol, third group was infected with IBV and fourth group was given carvacrol and infected with IBV. Infection with variant IBV induced significant upregulation of chicken interferon-inducible transmembrane protein 3 (chIFITM3) gene in trachea, elevations in serum levels of Alpha-1 acid glycoprotein (α1-AGP) and Interleukin 6 (IL-6), total leucocytic count (TLC), heterophil/lymphocyte (H/L) ratio and oxidative stress in lung and kidney tissues. Beside, histopathological changes in trachea, lung and kidney induced by IBV, elevation of kidney function tests was detected. The pretreatment with carvacrol significantly reduced viral shedding titer, chIFITM3 gene expression, IL-6 and α1-AGP levels, leucocytic response and H/L ratio with minimization of clinical signs intensity. Also, carvacrol relieved oxidative stress, ameliorated the increased uric acid level and histopathological alterations in kidney and lung caused by viral infection.

Behaviour and animal welfare indicators of broiler chickens housed in an enriched environment

The present study aimed to assess the influence of adding straw bales, step platforms, and laser projectors as environmental enrichment resources on the behaviour and welfare indicators of broiler chickens (Gallus gallus domesticus). A sample of 4,000 day-old male Cobb® 500 birds was used. The experimental treatments consisted of No Environmental Enrichment (NEE)-similar to a conventional environment; and Environmental Enrichment (EE)-environment enriched with straw bales, step platforms, and laser projectors, with four replicates per treatment of 500 animals. Behavioural characteristics (ethological observation through cameras, grab test, and modified touch test) and animal welfare indicators (pododermatitis and dorsal cranial myopathy) were assessed. The birds submitted to the EE treatment exhibited greater exploratory activity and expression of behaviours associated with comfort and welfare, whereas those in the NEE group were less active. Locomotion and play fighting behaviour decreased and behaviours associated with comfort increased as age advanced. The frequencies of interaction with laser spots and birds lying around straw bales were the highest in the 1st week (P<0.01). The behaviours of pecking at straw bales (P<0.0004), using the step platforms (P = 0.0001) and being on top of straw bales (P<0.0002) gradually increased. The chickens accessed the feeding troughs the most in the period of 0800 hours (P<0.0001) and expressed the highest frequencies of behaviours associated with comfort in the 1400 hours and 1700 hours periods. The birds in the EE group were calmer in face of human presence and touch and scored higher in animal welfare indicators. Adding straw bales, step platforms, and laser projectors increased locomotion, reduced expression of fear, and improved animal welfare indicators of broiler chickens.

Effects of an Elevated Platform on Welfare Aspects in Male Conventional Broilers and Dual-Purpose Chickens

To avoid killing day-old male chicks, one possibility is to keep dual-purpose chicken strains. Here, the hens were kept for egg production, and the roosters were kept for meat production. Both sexes had moderate performances compared to the respective hybrid chicken strains. However, until now, little has been known about whether male dual-purpose chickens may profit from enrichment in the environment in which broiler chickens are raised under conventional conditions. This study aims to further investigate the suitability of elevated structures for dual-purpose chickens (Lohmann Dual) with moderate growth and for fast-growing male broiler chickens (Ross 308). In two consecutive trials, we kept 686 Ross and 672 Dual chickens in 24 compartments (2 trials × 2 strains × 6 compartments). Half of the compartments were equipped with elevated grid platforms at a height of 50 cm (enriched group). In the other half of the compartments, no platforms were installed (control group). We analyzed the usage of the elevated platforms by scan sampling and assessed animal-based (walking ability, plumage cleanliness, and foot health) and management-based (litter quality) indicators. Both strains showed increasing use of the elevated platforms from the first week of life onwards. However, the fast-growing chickens used the elevated platform less than the slow-growing chickens. At the end of the fattening period, the birds used the elevated grids more at night than during the daytime. Slow-growing chickens kept in enriched compartments showed a better walking ability. In general, slow-growing chickens had better plumage conditions and foot health compared to fast-growing chickens. Our results show that natural behaviors such as perching can be supported by offering elevated platforms and that animal-based indicators such as walking ability can be improved, at least in slow-growing chickens. Moreover, the use of an alternative chicken strain avoids killing day-old male chicks, and in addition, these chickens show fewer animal welfare problems than a conventional fattening strain. Thus, the use of male chickens of a dual-purpose strain can substantially contribute to improving animal welfare in broiler meat production.

Leg health of meat chickens: impact on welfare, consumer behaviour, and the role of environmental enrichment

The Australian and global chicken meat industries have benefited from rapid improvements in the efficiency of chicken meat production that have been predominantly achieved through genetic selection, optimisation of bird nutrition and improved bird health. However, this has also resulted in morphological changes in the bird with an increase in the prevalence of leg health disorders. Compromised leg health can cause pain and lameness and bodes poorly for bird wellbeing, bird mortality, and economic returns. There are also implications for the consumer who is increasingly mindful of animal welfare and is demanding more welfare friendly products. Accurate on-farm assessment of bird leg health has challenges due to the diversity of leg disorders and the variety of techniques used to assess their severity and impact. Overall prevalence of leg disorders shows great variability between properties (farms) and flocks. Opportunities to improve bird leg health have been the focus of considerable research which has frequently included an evaluation of environmental enrichment as a means to reduce lameness and improve bird mobility. To this end, currently in Australia, 78% of chicken meat is produced under the conditions of the Australian RSPCA Approved Farming Scheme, which requires perches in the birds’ environment. However, the value of perches in providing enrichment and improving bird welfare is unclear. Therefore, this review explores animal welfare and consumer attitudes towards meat chicken welfare, describes leg disorders, outlines techniques for assessing leg health and discusses opportunities to enrich the birds’ environment to improve bird mobility and leg health.

Effects of environmental enrichment on health and bone characteristics of fast growing broiler chickens

Providing environmental enrichment for broilers is a potential strategy to increase welfare, activity, and health. The aim of this study was to evaluate the effect of environmental enrichment on health and leg bone characteristics of broilers. One control and 8 types of enrichment were included: 2 distances between food and water (7 and 3.5 m), roughage, vertical panels, straw bales, 2 platforms (30 and 5 cm), and a lowered stocking density (34 kg/m2). Birds were kept according to conventional Danish guidelines. The study included 58 pens with approximately 500 birds each. On day 35 of age, 25 birds per pen were killed and included in a postmortem analysis of wooden breast, body condition scores, pathological conditions (femoral head necrosis, arthritis, tenosynovitis, fractures, tibial dyschondroplasia, and twisted tibiotarsus), muscle width of the lower leg, and tibiotarsus properties (bone strength, weight, length, and proximal diameter, middle diameter, and distal diameter). It was predicted that environmental enrichment would have a positive effect on pathology with the exceptions that environmental enrichment that increased activity would pose a risk factor for wooden breast development, and straw bales would be a risk factor for bacterial infections (arthritis, tenosynovitis, and femoral head necrosis). Furthermore, it was hypothesized that enriched groups would have increased muscle width, bone strength, and dimensions of the tibiotarsus. Broilers with 7 m between food and water had a longer distal diameter of the tibiotarsus than those with straw bales (P = 0.04). The birds provided with vertical panels had wider leg muscle than the treatments with roughage (P = 0.045), 3.5 m distance (P = 0.049), and straw bales (P = 0.044). No effects were found for the remaining outcomes. These results suggest that provision of vertical panels and increased distance between resources can result in larger muscle and bone dimension, possibly having a positive effect on leg health. Furthermore, the provision of environmental enrichment does not appear to be a risk factor for wooden breast or bacterial infection.

The Productivity and Financial Impacts of Eight Types of Environmental Enrichment for Broiler Chickens

Reduced mobility in broilers can contribute to leg health problems. Environmental enrichment has been suggested as one approach to combat this through stimulating increased physical activity. Past studies have tested the effect of environmental enrichments on bird behaviour, health and welfare, but few have estimated their financial impacts. This study tested the impact of eight types of environmental enrichment on enterprise net margin, accounting for direct intervention costs plus indirect effects via changes to bird mortality, weight, feed intake, feed conversion ratio, and foot pad dermatitis. The trial used 58 pens each containing approximately 500 broilers (Ross 308) at a stocking density of 40 kg/m². The environmental enrichments were: roughage, vertical panels, straw bales, elevated platforms (5 and 30 cm), increased distances between feed and water (7 and 3.5 m) and stocking density reduced to 34 kg/m², plus a control group. Mortality was recorded daily and feed intake and weight weekly. Footpad dermatitis was assessed on day 35. Only one intervention improved financial performance (3.5 m between feed and water) above the control, suggesting that most environmental enrichment would have a negative financial impact due to the additional intervention costs, unless consumers were willing to pay a price premium.

Effects of Outdoor Access and Indoor Stocking Density on Behaviour and Stress in Broilers in the Subhumid Tropics

Studies investigating the welfare of commercial-line broiler chickens raised in houses with outdoor access in the tropics are scarce, and none have investigated whether responses vary according to indoor conditions. Hence, we assessed the effects of providing outdoor access at two indoor stocking densities on broiler chickens' growth, behaviour, stress responses and immunity in a tropical region of Mexico. One hundred and sixty chickens were assigned to one of four treatments in a factorial design: with or without outdoor access and low or high stocking density indoors. Ad libitum sampling was used to build a purpose-designed ethogram. Scan sampling was used to record the number of birds engaged in each activity of this ethogram, both indoors and outdoors. Heterophil/lymphocyte (H/L) ratio and serum corticosterone levels were tested in weeks four and six of age. When the birds were 42 days old, they were slaughtered, and the bursa and spleen harvested and weighed. In an interaction between stocking density and outdoor access, birds at the high stocking density with no outdoor pens spent the least time walking and preening and more time lying (p < 0.05). Birds given outdoor access foraged more, but only at indoor low stocking densities (p < 0.05). Outdoor access reduced heterophil/lymphocyte ratio, indicating reduced stressor response. Birds with low stocking density indoors and outdoor access appeared more responsive to stressors, with elevated corticosterone and reduced spleen and bursa weights (p < 0.05). There were welfare benefits of outdoor access, principally in terms of increased activity, which were reflected in slower growth in the birds with outdoor access.

On-farm broiler chicken welfare assessment using transect sampling reflects environmental inputs and production outcomes

To evaluate the utility of transect sampling for assessing animal welfare in large chicken flocks, we quantified relationships between environmental inputs, welfare problems detected using transect sampling, and production outcomes. We hypothesised that environmental inputs including environmental complexity (i.e. number of environmental enrichment types provided), space allowance, underfloor heating (presence or absence), and photoperiod regimen (18 h continuous vs 16 h intermittent) would correspond to variations in welfare assessment findings, which would predict production outcomes. We conducted on-farm welfare assessment of Norwegian broiler flocks at approximately 28 days of age. We sampled four transects (rows between feeder and drinker lines) per flock to determine litter quality and the proportions of chickens with compromised welfare as indicated by visual signs of walking difficulties, illness, skin wounds and small bird size. Production outcome measures included mortality, reasons for carcass rejection at slaughter, footpad dermatitis, growth rate, feed conversion and an integrated production index. Greater environmental complexity was associated with a reduction in skin wounds and total welfare problems on the farm, lower mortality, fewer rejections due to wounds and underweight birds, and fewer rejections overall. Higher space allowances within levels of environmental complexity were associated with fewer walking difficulties and welfare problems overall, a reduction in rejections due to wounds, and a higher growth rate and production index. Underfloor heating was associated with a reduction in rejections due to leg deformity, and intermittent light was associated with lower illness and skin wound rates on the farm, and lower mortality. Furthermore, fewer welfare problems and better litter quality on the farm were associated with fewer carcass rejections at slaughter. Thus, data from transect sampling varied with environmental inputs and production outcomes, supporting the validity of transect sampling for practical, animal-based on-farm welfare assessment.

Acute phase proteins and stress markers in the immediate response to a combined vaccination against Newcastle disease and infectious bronchitis viruses in specific pathogen free (SPF) layer chicks

Vaccination is an important tool in poultry health, but is itself a stressor often resulting in a reduction in feed intake, body weight gain, and nutrient digestibility. In other species, vaccination is associated with an immediate acute-phase response. As an important immune parameter, the circulating heterophil/lymphocyte (H/L) ratio is a well-recognized parameter of stress in poultry. In this study, the effects of a routinely used commercial poultry vaccine on the acute phase response (APR) and H/L ratios in specific pathogen-free (SPF) layer chicks was examined to determine if post vaccination (PV) stress and an APR occur. A combined Newcastle disease and infectious bronchitis vaccine (Nobalis Ma5+Clone 30) was administered to SPF chicks by the intraocular route at age 7 d. Acute phase proteins (APP), alpha-1 acid glycoprotein (AGP) and serum amyloid A (SAA) were measured by enzyme-linked immunosorbent assays at d 0 (pre-vaccination) and d 0.5, 1, 2, 3, 4, 5, 6, and 21 PV. Stress was determined in the chicks by measurement of the H/L ratio. The immune response to the vaccine was estimated by measurement of the antibody (IgY) response to the vaccine at d 21.The antibody titer was significantly (P < 0.05) higher in the vaccinated group at 21 d PV, confirming stimulation of the immune system. The H/L ratio was also significantly higher in the vaccinated group at 1 to 2 d (P < 0.01) and at 3 d (P < 0.05) PV. The concentration of SAA increased by 2.8-fold, from 63.7 μg/mL in controls to 181 μg/mL in the vaccinated group, (P < 0.05) at 1 d PV. AGP increased 1.6-fold at 2 d PV, (from 0.75 g/mL in the control group to 1.24 g/mL in the vaccinated group, P < 0.05).In conclusion an immediate but mild APR occurred in the chicks following intraocular vaccination, whereas the stress response as measured by H/L ratio seemed to be more specific and sensitive. Measurement of these biomarkers of the host response could be a tool in vaccine development.

Evaluating the effects of bedding materials and elevated platforms on contact dermatitis and plumage cleanliness of commercial broilers and on litter condition in broiler houses

1. Experiment 1, comparing wood shavings and ground straw bedding with peat, was performed on 7 broiler farms over two consecutive batches during the winter season. Experiment 2, assessing the effect of elevated (30 cm) platforms, was conducted in three farms replicated with 6 consecutive batches. 2. Footpad lesions were inspected at slaughter following the Welfare Quality® (WQ) assessment and official programme. Hock lesions, plumage cleanliness and litter condition were assessed using the WQ assessment. Litter height, pH, moisture and ammonia were determined. 3. Footpad condition on wood shavings appeared to be worse compared with peat using both methods of assessment and was accompanied by inferior hock skin health. WQ assessment resulted in poorer footpad and hock skin condition on ground straw compared with peat. Farms differed in footpad and hock skin condition. Footpad and hock lesions were not affected by platform treatment. Peat appeared more friable than ground straw. The initial pH of wood shavings was higher and moisture was lower than in peat, but at the end of production period there were no differences. Ground straw exhibited higher initial and lower end pH, and was drier in the beginning than peat. Litter condition and quality were not affected by platform treatment. 4. This study provides new knowledge about the applicability of peat as broiler bedding and shows no negative effects of elevated platforms on litter condition or the occurrence of contact dermatitis in commercial environments. The results suggest a complicated relationship between litter condition, moisture and contact dermatitis. Furthermore, it is concluded that the farmer's ability to manage litter conditions is important, regardless of the chosen litter material. Peat bedding was beneficial for footpad and hock skin health compared with wood shavings and ground straw.