Health, welfare and lifetime performance implications of alternative hatching and early life management systems for broiler chickens

Broiler chicks are typically hatched in a hatchery, exposing them to handling and transportation before being placed on the farm where (dry) feed and water is offered. This study compared different early life systems, including: (1) typical practice (control), (2) typical practice with wet feed offered upon placement, (3) access to water at the hatchery, (4) access to feed and water at the hatchery, (5) hatching on the farm. Birds were placed in groups of approximately 500 (day 0), with six replicates per treatment. Measures were taken between placement and slaughter (day 39) and included chick quality (navel and red hock scores), body weight, feed conversion ratio (FCR), mortality, gait and litter conditions scores, and behavioral and post-mortem assessments. There were no apparent treatment effects on gait score, play behaviour or novel object test measures, and no consistent effects on litter quality. Chick quality was only evaluated in Treatments 1 and 5 and was numerically worse in Treatment 5. Body weight at slaughter was lowest in Treatment 2, and did not differ between other treatments. Overall FCR was lowest (best) in Treatment 1, and did not differ between other treatments. There was higher overall mortality in Treatments 3 and 4 than in other treatments apart from Treatment 5. Treatment 4 appeared to promote feeding behaviour upon placement, and Treatment 5 birds rested the most, significantly more than in Treatment 2. Treatment 5 birds had the greatest bursa weights, and tibial dyschondroplasia appeared worse in Treatment 4. There were no consistent effects of early access to feed and water on gastrointestinal tract weight measures at slaughter. Compared to the control, there were few benefits in providing feed and/or water in the hatchery, or wet feed. Some benefits of in-house hatching were found, but negative effects were also apparent.

In ovo probiotic supplementation supports hatchability and improves hatchling quality in broilers

In modern broilers, the period of embryonic development constitutes a greater proportion of a broiler's productive life. Hence, optimum embryonic development can exert a significant influence not only on chick hatchability and hatchling quality but also on overall broiler growth and performance. Further healthy and active hatchlings are correlated with improved posthatch performance. In this regard, probiotics are good candidates to mediate early-life programming. Therefore, we evaluated the effect of In ovo probiotic spray application on broiler hatchability and hatchling quality. The experiment was set out as a completely randomized study with 2 independent trials. In each trial, 540 eggs (Ross 308) were either sprayed with phosphate buffered saline (PBS; control) or probiotics [∼9 log CFU/egg of Lactobacillus rhamnosus NRRL B-442(LR) or Lactobacillus paracasei DUP 13076 (LP)] during incubation. On day 18, eggs were transferred to the hatcher and set up for hatching. Starting on day 19, eggs were observed for hatching to determine the spread of hatch and hatchability. Hatched chicks were then assessed for quality using the Tona and Pasgar score and morphometric measurements including hatchling weight, yolk-free-body-mass and hatchling length were measured. Further, chicks were reared in floor pens for 3 wk to assess posthatch growth. Overall, In ovo probiotic supplementation improved hatchability and hatchling quality. Specifically, the spray application of LP improved hatchability by ∼ 5% without affecting the spread of hatch. Further, both LR and LP significantly improved Pasgar and Tona score, indicating an improvement in hatchling quality. Also, LP and LR significantly improved hatchling weight, yolk-free-body-mass, and posthatch growth in chicks. LR significantly improved hatchling weight and hatchling length (P < 0.05). Moreover, this increase in posthatch growth was positively correlated with hatchling weight in the probiotic groups. Overall, our study demonstrates that In ovo probiotic application exerts a positive effect on hatchability, hatchling quality, and subsequent posthatch growth.

Impact of early posthatch feeding on the immune system and selected hematological, biochemical, and hormonal parameters in broiler chickens

Under commercial conditions, chicks hatch within a 24 to 48 h window, a period known as the hatching window. Subsequently, they undergo various treatments before finally being transported to the broiler farm. These procedures may delay the chicks' access to food and water, sometimes receiving them as late as 72 h after hatching. Previous studies have indicated that fasting during this initial period is detrimental, leading to impaired body growth, compromised immune system response, and hindered muscle development. The objective of this study was to assess the impact of early posthatch feeding on immune system organs and selected hematological, biochemical, and hormonal parameters. The experiment utilized Ross 308 broiler eggs incubated under typical commercial hatchery conditions. The experimental group's eggs were hatched in HatchCare hatchers (HC) with immediate access to feed and water, while the control group's eggs were hatched under standard conditions (ST). Thirty chickens from each group were assessed on the 1st (D1), 7th (D7), 21st (D21), and 35th (D35) day after hatching. On D1, the HC group exhibited lower hemoglobin, hematocrit, and total serum protein values, suggesting that early access to water prevents initial dehydration in newborn chicks. Conversely, the ST group showed a stress reaction on D1 due to feed deprivation, leading to an almost 2-fold higher serum corticosterone concentration compared to the HC group. However, this increase did not result in a significant change in the heterophil/lymphocyte ratio. Furthermore, the HC group displayed an increase in triglyceride concentration and a decrease in HDL concentration on D1. On D7, the HC group exhibited an increased relative weight of the bursa and a higher CD4+ cell number in the cecal tonsil (CT), indicating a more rapid development of these organs resulting from early stimulation of the gastrointestinal tract. However, early feeding did not influence the numbers of Bu-1+, CD4+, and CD8+ cells or the germinal center (GC) areas in the spleen. In conclusion, early feeding contributes to the welfare of newborn chicks by reducing dehydration and stress levels and stimulating the development of gut-associated lymphoid tissue.

Effects of algal supplementation in feed to broiler breeders on transfer of nutrients and antibodies to chicks and quality of hatchlings

Breeder nutrition is an important factor for chick quality since the chick embryo relies on nutrients available in the egg for growth and development. In addition, the egg is providing the chick with important antibodies that are vital during the first weeks of life. Brown algae contains several bioactive compounds, and dietary supplementation with algal extracts have shown improved gut health and immune responses in both pigs and poultry. The aim of this study was to investigate if feeding the brown algae Saccharina latissima, intact or as an extract, to broiler breeders can affect breeder hens' antibody responses to vaccination, egg quality and transfer of antibodies and nutrients to the egg and thereby improve the quality of newly hatched chicks. Forty-five hens and nine roosters of the parent lines of the fast-growing broiler Ross 308 were included in the experiment where hens were 31 weeks at the start. The hens were housed individually and fed one of three dietary treatments for seven weeks; (a) control, (b) addition of 0.6% algal meal or (c) addition of 0.08% algal extract. The hens were given a booster vaccination against infectious bronchitis virus (IBV) 21 days after the start of experiment. During experimental days 32-42, hens were naturally mated every 5th day and hatching eggs were collected. A total of 255 chicks were hatched, and chick quality was assessed. Moreover, on chick day three, blood was collected from 48 focal chickens and total immunoglobulin Y levels and specific titres to IBV in serum were determined. The results showed that feeding the brown algae Saccharina latissima, intact or as an extract to broiler breeders did not affect egg production, egg quality, antibody responses to vaccination or transfer of antibodies from hen to chick. However, feeding intact algae significantly increased the levels of iodine and decreased the level of selenium in the eggs and resulted in a lower proportion of chicks with maximum quality score. Interestingly, algal feeding, both intact and as an extract, increased the abdominal fat pad in broiler breeders by about 17% without affecting BW. In conclusion, supplementation of broiler breeder diets with algal extract from Saccharina latissima, but not intact algal meal is a promising dietary strategy to increase the abdominal fat pad without causing any adverse effects on nutrient level in eggs or chick quality.

Factors influencing the development of gastrointestinal tract and nutrient transporters' function during the embryonic life of chickens-A review

Intestinal morphology and regulation of nutrient transportation genes during the embryonic and early life of chicks influence their body weight and feed conversion ratio through the growing period. The intestine development can be monitored by measuring villus morphology and enzymatic activity and determining the expression of nutrient transporters genes. With the increasing importance of gut development and health in broiler production, considerable research has been directed towards factors affecting intestine development. Thus, this article reviews (1) intestinal development during embryogenesis, and (2) maternal factors, in ovo administration, and incubation conditions that influence intestinal development during embryogenesis. Conclusively, (1) chicks from heavier eggs may have a better-developed intestine than chicks from younger ones, (2) in ovo supplementation with amino acids, minerals, vitamins or a combination of several probiotics and prebiotics stimulates intestine development and increases the expression of intestine mucosal-related genes and (3) the long storage period, improper incubation temperature and imbalanced ventilation can negatively influence intestinal morphology and nutrient transporters gene expression. Finally, understanding the intestine development during embryonic life will enable us to enhance the productivity of broilers.

Physiological effects of in ovo delivery of bioactive substances in broiler chickens

The poultry industry has improved genetics, nutrition, and management practices, resulting in fast-growing chickens; however, disturbances during embryonic development may affect the entire production cycle and cause irreversible losses to broiler chicken producers. The most crucial time in the chicks' development appears to be the perinatal period, which encompasses the last few days of pre-hatch and the first few days of post-hatch. During this critical period, intestinal development occurs rapidly, and the chicks undergo a metabolic and physiological shift from the utilization of egg nutrients to exogenous feed. However, the nutrient reserve of the egg yolk may not be enough to sustain the late stage of embryonic development and provide energy for the hatching process. In addition, modern hatchery practices cause a delay in access to feed immediately post-hatch, and this can potentially affect the intestinal microbiome, health, development, and growth of the chickens. Development of the in ovo technology allowing for the delivery of bioactive substances into chicken embryos during their development represents a way to accommodate the perinatal period, late embryo development, and post-hatch growth. Many bioactive substances have been delivered through the in ovo technology, including carbohydrates, amino acids, hormones, prebiotics, probiotics and synbiotics, antibodies, immunostimulants, minerals, and microorganisms with a variety of physiological effects. In this review, we focused on the physiological effects of the in ovo delivery of these substances, including their effects on embryo development, gastrointestinal tract function and health, nutrient digestion, immune system development and function, bone development, overall growth performance, muscle development and meat quality, gastrointestinal tract microbiota development, heat stress response, pathogens exclusion, and birds metabolism, as well as transcriptome and proteome. We believe that this method is widely underestimated and underused by the poultry industry.

Effects of hatching system on chick quality, welfare and health of young breeder flock offspring

Alternative hatching systems have been developed for broiler chickens to provide immediately feed and water after hatch and reduce the number or severity of early life stressors. Besides beneficial effects of these alternative hatching systems on chick quality and performance, broiler health and welfare may be positively affected as well. Especially offspring from young broiler breeder flocks may benefit, as they have been shown to be more sensitive to preturbations than offspring from older breeder flocks. This study evaluated effects of hatching systems on chick quality, health and welfare of young breeder flock offspring, using 3 different hatching systems: conventional hatchery-hatched (HH), hatchery-fed (HF), and on-farm hatching (OH). A total of 24 pens were used in a completely randomized block design, with 8 pens per hatching system and 30 chickens per pen. Chick quality at hatch and performance until 35 d of age was improved in the HF and OH compared to HH treatment, but only minor effects were found on the welfare indicators: footpad dermatitis, hock burn, cleanliness, skin lesion and gait score. No effect was observed on the dynamics of a humoral immune response after NCD vaccination, given at d 0 and 14 of age, as no differences between NCD titers were found at d 18. Animals were vaccinated with a live attenuated infectious bronchitis vaccine virus (IBV) at d 28 to address treatment related differences to disease resilience. The expressions of inflammation and epithelial integrity related genes in the trachea and histo-pathological changes in the trachea were examined at 3 d after vaccine administration. No differences between treatment groups were observed. Although beneficial effects of HF and OH systems were found for young breeder flock offspring on chick quality at hatch and body weight posthatch, only one effect of alternative hatching systems on welfare and health indicators were found. No effect of hatching system on humoral immune response or disease resilience was found.

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.

Delayed access to feed early post-hatch affects the development and maturation of gastrointestinal tract microbiota in broiler chickens

Background

The first two weeks of post-hatch (PH) growth in broilers (meat-type birds) are critical for gut development and microbiota colonization. In the current broiler production system, chicks may not receive feed and water for 24 to 72 h due to variations in hatching time and hatchery management. Post-hatch feed delay affects body weight, feed efficiency, mortality, and gut development. The goal of this study was to investigate changes in the microbiome in broiler chickens early PH and the effect of delayed access to feed on the microbiota.

Results

Chicks either received feed and water immediately after hatch or access to feed was delayed for 48 h to mimic commercial hatchery settings (treatment, TRT). Both groups were sampled (n = 6) at -48, 0, 4 h, and 1 (24 h), 2 (48 h), 3 (72 h), 4 (96 h), 6 (144 h), 8 (192 h), 10 (240 h), 12 (288 h) and 14 (336 h) days PH. Ileal (IL) and cecal (CE) epithelial scrapings (mucosal bacteria, M) and digesta (luminal bacteria, L) were collected for microbiota analysis. Microbiota was determined by sequencing the V3-V4 region of bacterial 16S rRNA and analyzed using QIIME2. The microbiota of early ileal and cecal samples were characterized by high abundance of unclassified bacteria. Among four bacterial populations (IL-L, IL-M, CE-L, CE-M), IL-M was the least affected by delayed access to feed early PH. Both alpha and beta diversities were affected by delayed access to feed PH in IL-L, CE-M and CE-L. However, the development effect was more pronounced. In all four bacterial populations, significant changes due to developmental effect (time relative to hatch) was observed in taxonomic composition, with transient changes of bacterial taxa during the first two weeks PH. Delayed access to feed has limited influence on bacterial composition with only a few genera and species affected in all four bacterial populations. Predicted function based on 16S rRNA was also affected by delayed access to feed PH with most changes in metabolic pathway richness observed in IL-L, CE-L and CE-M.

Conclusions

These results show transient changes in chicken microbiota biodiversity during the first two weeks PH and indicate that delayed access to feed affects microbiota development. Proper microbiota development could be an important factor in disease prevention and antibiotic use in broiler chickens. Moreover, significant differences in response to delayed access to feed PH between luminal and mucosal bacterial populations strongly suggests the need for separate analysis of these two populations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-022-02619-6.

Antimicrobial resistance in Escherichia coli isolated from on-farm and conventional hatching broiler farms in Ireland

Background

On-farm hatching (OH) systems are becoming more common in broiler production. Hatching conditions differ from conventional farms as OH chicks avoid exposure to handling, transport, post-hatch water and feed deprivation. In contrast, chicks in conventional hatching conditions (CH) are exposed to standard hatchery procedures and transported post hatching. The objectives of this pilot study were to investigate the prevalence and frequency of Escherichia coli resistant to antimicrobials, including presumptive ESBL/AmpC-producing E. coli, isolated from environmental and faecal samples from OH versus CH hatching systems, and to investigate the presence of ESBL/AmpC-producing encoding genes.

Results

Environmental samples were collected from one flock in 10 poultry farms (5 OH farms, 5 CH farms) on day 0 post disinfection of the facilities to assess hygiene standards. On D10 and D21 post egg/chick arrival onto the farm, samples of faeces, boot swabs and water drinker lines were collected.

E. coli were isolated on MacConkey agar (MC) and MacConkey supplemented with cefotaxime (MC+). Few E. coli were detected on D0. However, on D10 and D21 E. coli isolates were recovered from faeces and boot swabs. Water samples had minimal contamination. In this study, 100% of cefotaxime resistant E. coli isolates (n=33) detected on selective media and 44% of E. coli isolates (84/192) detected on nonselective media were multidrug resistant (MDR). The antimicrobial resistance (AMR) genotype for the 15 ESBL/AmpC producing isolates was determined using multiplex PCR. Six of these were selected for Sanger sequencing of which two were positive for bla_CMY-2, two for bla_TEM-1 and two were positive for both genes.

Conclusions

There was no difference in E. coli isolation rates or prevalence of AMR found between the OH versus CH systems, suggesting that the OH system may not be an additional risk of resistant E. coli dissemination to broilers compared to the CH systems. The frequency of β-lactam resistant E. coli in boot swab and faeces samples across both OH (24/33 (73%)) and CH (9/33 (27%)) systems may indicate that hatcheries could be a reservoir and major contributor to the transmission of AMR bacteria to flocks after entry to the rearing farms.

Storage Temperature or Thermal Treatments During Long Egg Storage Duration Influences Hatching Performance and Chick Quality

This study was designed to improve the hatching performance, chick robustness and poultry health in the event of long-term egg storage and suboptimal age of the reproductive flock. A total of 9,600 eggs from one young breeder flock (28 weeks of age, batch B) and 9,600 eggs from an older breeder flock (59 weeks of age, batch E) were used (ROSS 308). Each batch was separated into three sub-groups and stored for 14 days. The first sub-group of eggs (Cool, group C) was stored at 11.6°C. The second sub-group of eggs (Warm, group W) was stored at 18.3°C with two pre-incubation on days 6 and 10 of the storage period. The final sub-group of eggs (Control, group Ct) was stored at 18.3°C throughout the storage period. Eggs were similarly incubated and hatched birds were raised on the same experimental farm. In both batches, embryonic development was significantly more advanced in W eggs than in C and Ct eggs ( p < 0.01). In both batches, C and W treatments decreased early embryonic mortality by more than 10% compared with Ct, decreased the proportion of late-hatched chicks and improved the percentage of first grade chicks: in batch E, 42% of Ct eggs were first grade chicks vs. 57% in group W and 59% in group C. Benefits were even higher in batch B, where only 60% of Ct eggs gave first grade chicks vs. 83% in others groups. The hatching rate was thus higher in groups C and W regardless of flock age: for batch B eggs, 85% hatched in W and 84% in C vs. 62% in Ct, while for batch E eggs, 59% hatched in W and 61% in C vs. 45% in Ct. Day-old Ct chicks from batch E were heavier than W and C ones, and heavier than W chicks from batch B ( p < 0.05). Long-term parameters on farm were not significantly different between groups. Thermal treatments during the storage of eggs from both young and old breeder flocks counterbalance the negative effects of prolonged egg storage on hatching rate, without altering chicken performance during rearing.

Research Note: Interaction between hatching time and chick pull time affects broiler live performance

This study investigated the effects of broiler chick hatching time and pull time on subsequent live performance. Hatching eggs were obtained from commercial broiler breeder flocks of Ross 308 at 29 and 30 wk of age in trials 1 and 2, respectively. Eggs were incubated in 2 identical setters on 2 consecutive days. In both trials, portion of the eggs (9,600), incubated on the first day of set, were assigned to delayed-pull (DP) treatment, and the other portion of the eggs (9,600), incubated on the second day of set, were assigned to normal-pull (NP) treatment. The hatching period was divided into 3 hatching time groups, and chicks were classified as hatching in the early (478 to 490 h), middle (490 to 496 h), or late period (496 to 510 h of incubation). At 510 h of incubation based on the NP set date, all chicks were transferred to a broiler research house. A total of 7,200 and 8,400 chicks within 2 chick pull time treatments × 3 hatching time groups were raised in trials 1 and 2, respectively. The primary difference between the DP and NP treatments was an additional 24 h holding period in the hatcher for the DP group. Therefore, chick BW was higher at placement in the NP treatment than in the DP treatment (P < 0.001). However, this advantage disappeared by 7 d, and the average BW did not differ between the DP and NP treatments at 41 d. Chick pull time did not affect feed consumption or feed conversion ratio (FCR) at 41 d. Similar to pull time, hatching time did not impact BW, feed consumption or FCR at 41 d. However, for mortality and European Production Efficiency Index (EPEI) at 41 d, a hatching time × pull time interaction was observed (P < 0.001). Mortality was higher and EPEI was lower in late hatch chicks than in chicks hatched early and middle in the NP treatment, whereas for chicks in the DP treatment, mortality and EPEI did not differ among the hatching time groups. These data indicated that the DP treatment, which held the chicks for an additional 24 h in the hatcher under optimum conditions, produced a lower initial BW accompanied by a period of compensatory weight gain through 41 d, and no differences (P > 0.05) in live performance occurred due to the holding time in the hatcher. Overall, sending the late hatched chicks to the broiler house shortly after hatching increased their mortality and negatively affected their live performance (as measured by EPEI), unlike holding early hatched chicks for a relatively long time after hatching (50 h) in the hatcher.

Effects of Early Nutrition of Hatched Chicks on Welfare and Growth Performance: A Pilot Study

Simple Summary

It is common practice that one-day-old chicks can be deprived of feed for about 48 h or more before they are housed on farms. Thus, we hypothesized that early nutrition on-farm hatched chicks might overcome the adverse effects of delayed nutrition on-hatchery hatched chicks regarding some animal welfare issues such as foot pad health as well as growth performance of birds. Our results confirmed that early nutrition on-farm hatched chicks together with using new fresh litter at d 7 of life led to a reduction in the severity of foot pad lesions and improved the growth performance of broiler chickens.

Abstract

This study aimed to investigate the possibility of rearing newly hatched chicks with immediate access to feed and water in the same hatching unit one week prior to transferring them to the conventional broiler house with special regards to foot pad health and growth performance. Two trials were performed with a total of 6900/6850 (trials 1/2) broiler chickens (ROSS 308). A total of 3318/3391 chicks (trials 1/2) were transported from the hatchery (duration of about 3 h) and reared in a conventional broiler house (control group: delayed nutrition on-hatchery hatched). The control group did not receive any form of nutrition until they were taken to conventional broiler housing. Additionally, a total of 3582/3459 (trials 1/2) embryonated eggs (d 18) were obtained from the same parent flock of the same commercial hatchery and taken to the farm facility. After on-farm hatch, the chicks had immediate access to water and feed (experimental group: early nutrition on-farm hatched). After d 6/7 of life, the on-farm hatched chicks (trials 1/2) were transferred to the broiler house on the same facility. The delayed nutrition on-hatchery hatched groups displayed a significantly lower dry matter content in the litter compared to the early nutrition on-farm hatched groups (two-factorial analysis) at d 6/7 and d 14 of life. However, thereafter, no significant differences were noted. Based upon two-factorial analysis, the early nutrition on-farm hatched groups revealed lower foot pad lesions from d 14 of life onwards and showed a higher body weight (BW) throughout the rearing period compared to the delayed nutrition on-hatchery hatched groups (p < 0.05). Overall, early nutrition on-farm hatched chickens is of critical importance together with using new litter at d 7 to maintain healthy foot pads as well as to enhance nutrient utilization and optimize the growth performance.

Effects of hatching on-farm on performance and welfare of organic broilers

As an alternative to traditional hatching in the hatchery, fertilized incubated eggs can be placed in the rearing barn on embryonic d 18 for hatching to occur on-farm, omitting several hatchery procedures, and transport of day-old chicks. In addition, this practice further allows newly hatched chicks access to feed and water immediately post-hatch. The aim of the present study was to examine welfare implications of hatching slower-growing organic broilers on-farm (OF) using the One2Born system (One2Born, Uden, the Netherlands). Hatchery-hatched chicks (HC) transported to the farm were used as control. Six flocks of both treatments, each comprising approximately 3,600 mixed-sex Hubbard JA57 ColorYield broilers, housed with veranda and outdoor access were included in the study. Compared to HC, the hatchability was higher in OF chicks (95.3% vs. 94.8%; P = 0.0097), whereas the number of second grade chicks was lower (11.6% vs. 16.1%; P < 0.0001). The chick quality was lower for OF than HC (odds ratio: 1.79; P = 0.0009), but this was not reflected in the first week mortality (OF: 0.41%, HC: 0.99%; P < 0.0001) or total mortality (OF: 1.51%, HC: 2.20%; P < 0.0001). No difference was found between treatments for the live body weight at slaughter age (P = 0.73). Breast blisters were more common in HC males than in OF males and in females from both treatments (P = 0.038), whereas OF males and females from the 2 treatments did not differ (P = 0.91). There was no effect of treatment on litter quality, footpad dermatitis, gait, skin injuries, and rejection rates at slaughter (P ≥ 0.35). In conclusion, OF hatching appears to be a viable concept, resulting in reduced mortality and increased hatchability, though knowledge on the topic is sparse. Therefore, more research should be addressed to the welfare implications of hatching OF, specifically to impacts on litter quality, footpad dermatitis, and how chick quality impacts other animal welfare indicators.

Effects of hatch window and nutrient access in the hatcher on performance and processing yield of broiler chicks reared according to time of hatch

The effects of hatch window and hatching basket nutrient availability on organ weights, performance, and processing yield of broilers were investigated. Eggs were hatched in illuminated hatchers. At the end of each hatch window period (HWP), hatched chicks were placed into control (CTL) hatching baskets with no nutrients or baskets providing access to feed and water (FAW). This resulted in 6 treatments in a factorial arrangement of 3 HWP (early, middle, or late) and 2 basket types (CTL or FAW). Chicks remained in experimental baskets until 504 h and were then subjected to a 4 h holding period at the hatchery without nutrient access. Subsequently, 1,500 hatched chicks were reared in floor pens for 42 d with 5 replicate pens per treatment. Common diets and water were provided ad libitum. Bird weights and feed consumption were recorded weekly. Individual bird weights were taken at 21 and 42 d. At 43 d, 14 males from each pen were processed. There was an interaction between HWP and basket type on placement BW (P = 0.028) and BW change in the hatcher (P < 0.001). The HWP influenced BW at hatch (P = 0.007), 7 d (P < 0.001), and 14 d (P < 0.001) and FI at 7 d (P < 0.001) and 14 d (P = 0.002). Chicks from FAW baskets were heavier (P < 0.001) than those from CTL baskets at 7 d; afterward, they were similar (P > 0.05) in BW. Yolk and liver weights were similar (P > 0.05) between basket treatments at 3 d posthatch. No differences (P > 0.05) in FCR, mortality, or processing were observed between basket treatments. Interestingly, early hatching chicks were lightest at hatch but subsequently had higher FI and BWG. These findings indicate that hatcher nutrient access may reduce weight loss in the hatcher, especially for early hatching chicks, but had no influence on subsequent performance or processing yields beyond 7 d.

Embryotoxicity and Physiological Compensation in Chicken Embryos Exposed to Crude Oil

Terrestrial, marine, or aquatic oil spills can directly or indirectly contaminate bird eggs. We hypothesized that chicken embryos exposed to crude oil can physiologically compensate to mitigate the potentially toxic effect of lower doses of oil. Embryos exposed to 0, 1, 3, or 5 µL of oil on embryonic days 4 and 10 were initially analyzed for mortality. All oil doses decreased day 4 embryo survival, but only the 2 highest oil doses lowered survival when applied on day 10. Thus, day 15 embryos treated with 1, 3, and 5 µL of source oil on day 10 had arterialized blood analyzed. The hematological variables hematocrit, red blood cell concentration ([RBC]), and hemoglobin concentration increased in response to 1 µL, were unchanged by 3 µL, and decreased by 5 µL of oil treatment. No changes occurred in arterialized blood gas variables (partial pressure of O₂ [PO₂ ], pH, bicarbonate concentration) for 1 and 3 µL embryos, but 5 µL of oil decreased PO₂ and caused metabolic acidosis. Increased blood lactate in embryos treated with 3 and 5 µL of oil was correlated with decreased hematocrit and [RBC] and increased body mass, the latter likely reflecting edema. We conclude that embryos in middle development physiologically compensated for negative effects of lower doses of crude oil but that higher doses of oil were harmful to the embryos at all developmental stages. Environ Toxicol Chem 2021;40:2347-2358. © 2021 SETAC.

The effect of delayed feeding post-hatch on caeca development in broiler chickens

1. Broiler chicks are frequently deprived of food up to 72 h due to uneven hatching rates, management procedures and transportation to farms. Little is known about the effect of delayed feeding due to extended hatching times on the early neonatal development of the caeca. Therefore, the objective of this study was to investigate the developmental changes and effects of a 48-h delay in feed access immediately post-hatch (PH) on the caeca.2. After hatch, birds (Ross 708) were randomly divided into two treatment groups (n = 6 battery pen/treatment). One group (early fed; EF) received feed and water immediately after hatch, while the second group (late fed; LF) had access to water but had delayed access to feed for 48 h. Contents averaging across all regions of the caeca were collected for mRNA expression as well as for histological analysis at -48, 0, 4 h PH and then at 1, 2, 3, 4, 6, 8, 10, 12 and 14 days PH.3. Expression of MCT-1 (a nutrient transporter), Cox7A2 (related to mitochondrial function) IgA, pIgR, and ChIL-8 (immune function) genes was affected by delayed access to feed that was dependent by the time PH. Expression of immune and gut barrier function-related genes (LEAP2 and MUC2, respectively) was increased in LF group. There was no effect of feed delay on expression of genes related to mitochondrial functions in the caeca, although developmental changes were observed (ATP5F1B, Cox4|1). Caecal mucus and muscle thickness were affected by delayed access to feed during caeca development.4. The data suggested a limited effect of delayed feed access PH on the developmental changes in caecal functions. However, the caeca seemed to be relatively resistant to delayed access to feed early PH, with only a few genes affected.

Day-old chicken quality and performance of broiler chickens from 3 different hatching systems

In on-farm hatching systems, eggs are transported at d 18 of incubation to the broiler farm, where chickens have immediate access to feed and water after hatching. In hatchery-fed systems, newly hatched chickens have immediate access to feed and water in the hatchery and are transported to the farm thereafter. Conventionally hatched chickens can remain without access to feed and water up to 72 h after hatching until placement on the farm. The current study compared day-old chicken quality, performance, and slaughter yield of broiler chickens that were on-farm hatched (OH), hatchery-fed (HF), or conventionally hatchery-hatched (HH). The experiment was performed in 6 rooms in 1 house. Each room contained 2 duplicate pens with approximately 1,155 chickens per pen; 2 rooms with each 2 duplicate pens were assigned to 1 treatment. The experiment was repeated during 3 consecutive production cycles. Chickens originated from young parent stock flocks. Results showed that HF and OH chickens were heavier and longer than HH chickens at day (D) 1. Relative weight of stomach and intestines were highest for OH chickens. The OH chickens had worse day-old chicken quality in terms of navel condition and red hocks than HH and HF chickens. Treatments did not differ in first wk and total mortality. From D0 until slaughter age, body weight was highest for OH, followed by HF and HH. Furthermore, carcass weight at slaughter age (D40) was highest for OH chickens, followed by HF and HH chickens. Breast fillets showed a higher incidence of white striping and wooden breast in HF and OH chickens compared with HH chickens. In conclusion, the current study showed that both OH and HF chickens of young parent flocks had better growth performance, which could explain the higher prevalence of breast myopathies, compared with HH. The worse day-old chicken quality for OH compared with HH and HF does not seem to affect first wk mortality and later life performance.

Effect of delayed feeding post-hatch on expression of tight junction- and gut barrier-related genes in the small intestine of broiler chickens during neonatal development

The gut not only plays a key role in digestion and absorption of nutrients but also forms a physical barrier and first line of defense between the host and the luminal environment. A functional gut barrier (mucus and epithelial cells with tight junctions [TJ]) is essential for optimal health and efficient production in poultry. In current broiler system, chicks are deprived of food and water up to 72 h due to uneven hatching, hatchery procedures, and transportation. Post-hatch feed delay results in lower BW, higher FCR and mortality, and delayed post-hatch gut development. Little is known about the effects of early neonatal development and delayed feeding immediately post-hatch on gut barrier function in chickens. Therefore, the aim of the present study was to characterize the expression pattern of gut barrier-related and TJ-related genes in the small intestine of broiler chickens during early development and delay in access to feed. Newly hatched chicks received feed and water immediately after hatch or were subjected to 48 h delayed access to feed to mimic commercial hatchery setting and operations. Birds were sampled (n = 6) at -48, 0, 4, 24, 48, 72, 96, 144, 192, 240, 288, and 336 h post-hatch. Jejunum and ileum were collected, cleaned of digesta, and snap-frozen in liquid nitrogen or fixed in paraformaldehyde. The relative mRNA levels of gut barrier- and TJ-related protein genes were measured by quantitative PCR and analyzed by 2-way ANOVA. In both tissues, changes (P < 0.05) in gene expression pattern of gut barrier-related and TJ-related genes were detected due to delayed access to feed post-hatch and/or development. In general, expression of TJ-related genes was downregulated while mRNA levels of gut barrier-related genes were upregulated during development. Histological differences and changes in mucin staining due to age and treatment were observed. These results suggest that delayed access to feed post-hatch may affect TJ structure and/or function and therefore gut barrier function and overall health of the chicken small intestine.

Effects of on-farm and traditional hatching on welfare, health, and performance of broiler chickens

In on-farm hatching systems, eggs that have been incubated for 18 D are transported to the broiler farm. After hatching around day 21, the chicks have immediate access to feed and water. By contrast, traditionally hatched chicks are in early life exposed to dust and pathogens in the hatcher, handling procedures, and transport and remain without feed and water until they have arrived on the farm 1 to 3 D after hatching. We compared welfare and performance of on-farm hatched (OH) and traditionally hatched control (C) Ross 308 broiler chickens from day 0 to 40, housed under semicommercial conditions. The experiment included 3 production cycles in 4 rooms, with each room containing 1 OH and 1 C pen with 1,150 chickens in each pen. Per cycle, C and OH chicks were from the same batch of eggs of 1 parent stock flock. Day-old chick quality was worse for OH than C chickens (hock and navel score; P < 0.05). On-farm hatched chickens were heavier than C chickens until day 21 of age (P < 0.05). Total mortality was significantly lower in OH compared with C pens (P < 0.05). A tendency for lower footpad dermatitis scores was found in OH pens compared with C pens (P < 0.10), probably because of the dryer litter in OH than C pens (P < 0.05). No differences between treatments were found in gait, hock burn, cleanliness, and injury scores, and no or only minor, short lasting differences were found in pathology and intestinal histology. In conclusion, the present study showed that on-farm hatching may be beneficial for broiler welfare, as it reduced total mortality and resulted in dryer litter which is known to be beneficial for reducing footpad dermatitis.

Effects of stage of broiler embryo development on coccidiosis vaccine injection accuracy, and subsequent oocyst localization and hatchling quality

Control of coccidiosis in broiler chickens continues to pose challenges to commercial poultry producers, especially in an era of increased consumer demand for antibiotic-free broiler production. As a result, coccidiosis vaccines are now commonly used in rotation programs to achieve effective coccidiosis control. Inovocox EM1 vaccine (EM1) is a coccidiosis vaccine that allows for earlier immune acquisition through oocyst cycling, which reduces the effects of wild-type coccidia. The EM1 vaccine is administered to embryonated broiler hatching eggs between 18 and 19 D of incubation (doi). In the U.S., commercial broiler hatcheries vaccinate embryonated eggs at either 18.5 or 19 doi. However, it is unclear whether a difference in embryo age at the time of in ovo injection can impact the actual site of vaccine delivery. In addition, it is unclear where oocysts eventually become localized within the embryo following the in ovo injection of EM1. Therefore, the objective of this study was to determine the effects of stage of embryonic development on the actual deposition site of the EM1 vaccine oocysts when they are in ovo injected and to subsequently investigate the movement and eventual location of EM1 oocysts after in ovo injection. Because all eggs were injected at the same time, a 12-h difference in set time was a means to derive 18.5 and 19.0 incubation age of injection (IAN) treatments. The experimental design was a 3 injection treatment (noninjected, diluent-injected, and vaccine-injected) × 2 IAN factorial. There was a significant main effect of IAN on site of vaccine oocysts delivery, and subsequent hatching chick quality. Qualitative histological evaluation revealed the oral uptake of vaccine oocysts through the amnion, with their subsequent presence in the gizzard and intestinal lumen by 24 to 36 h postinjection. In conclusion, physiological development influenced the site of injection, and oocysts imbibed along with the amniotic fluid in late stage broiler embryos are subsequently transported to the gastrointestinal tract.

Effect of early neonatal development and delayed feeding post-hatch on jejunal and ileal calcium and phosphorus transporter genes expression in broiler chickens

Calcium (Ca) and phosphorus (P) are essential minerals involved in many biological processes including bone development and mineralization. Plasma concentration of both minerals is tightly regulated, and Ca and P homeostasis is maintained via intestinal absorption, bone storage and exchange, and renal reabsorption. In the current broiler production systems, chicks are deprived of food and water for up to 72 h due to uneven hatching, hatchery procedures, and transportation time to farms. Post-hatch (PH) feed delay results in lower body and organ weight, higher feed conversion ratio and mortality, and delayed PH growth and GIT development. Little is known about the effects of early neonatal development and delayed or immediate feeding PH on Ca and P transporters. Therefore, the aim of the present study was to characterize expression patterns of Ca and P transporter genes in small intestine during the first 2 wk PH in chickens fed immediately after hatch (FED) or subjected to 48 h delayed feeding (NOTFED). Expression of all Ca and P transporters in jejunum and ileum was significantly (P < 0.05) affected by age. Among Ca transporter genes, only mRNA expression of Calbidin D28k in jejunum and Ca sensing receptor (CaSR) in ileum were significantly (P < 0.05) affected by delay in feed access. For P transporter genes' expression, only P transporter type III (PIT1) mRNA was significantly affected by age, delay in feed access, and their interaction (P < 0.05). In summary, we have shown, for the first time, early developmental changes of Ca and P transporter genes in broiler chickens. Results suggest that an increase in gene expression of some of the transporters corresponds with the switch from yolk to high starch diet. Overall, our results can be helpful in better understanding of Ca and P homeostasis in broilers.

Comparison of performance, health and welfare aspects between commercially housed hatchery-hatched and on-farm hatched broiler flocks

On-farm hatching systems for broiler chicks are increasingly used in practice. We studied whether or not performance, health and welfare aspects differed between commercial flocks hatched on-farm or in a hatchery (control). In two successive production cycles on seven farms, a total of 16 on-farm hatched flocks were paired to 16 control flocks, housed at the same farm. Paired flocks originated from the same batch of eggs and were subjected to similar on-farm management. On-farm hatched and control flocks only differed with respect to hatching conditions, with on-farm hatched flocks not being exposed to, for example, chick handling, post-hatch feed and water deprivation and transport, in contrast to control flocks that were subjected to standard hatchery procedures, subsequently transported and placed in the poultry house. Day-old chick quality (navel and hock scores), 1st week mortality, total mortality, BW at day (d) 0, d7 and at depopulation, and (total) feed conversion ratio were determined. Prevalence of footpad dermatitis, hock burn, breast discoloration/blisters and cleanliness, litter quality and gait score were determined at d21 of age and around depopulation (d39 on average). Gross pathology and gut morphology were examined at depopulation age in a sample of birds of five flocks per treatment. On-farm hatching resulted in a higher BW at d0 (Δ=5.4 g) and d7 (Δ=11.5 g) (P&lt;0.001), but day-old chick quality as measured by navel (P=0.003) and hock (P=0.01) quality was worse for on-farm hatched compared to control birds. Body weight, 1st week and total mortality, and feed conversion ratio at slaughter age were similar for both on-farm hatched and control flocks. On-farm hatched flocks had less footpad dermatitis (P=0.05), which indicated a better welfare. This was likely related to a tendency for better litter quality in on-farm hatched flocks at 21 days of age in comparison to control flocks (P=0.08). No major differences in gross pathology or in intestinal morphology at depopulation age were found between treatments. In conclusion, on-farm hatching resulted in better 1st week broiler performance and better welfare compared to conventional hatching in a hatchery.

Effects of mixing eggs of different initial incubation time on the hatching pattern, chick embryonic development and post-hatch performance

Background

The hatch window that varies from 24 to 48 h is known to influence post-hatch performance of chicks. A narrow hatch window is needed for commercial poultry industry to acquire a high level of uniformity of chick quality. Hatching synchronization observed in avian species presents possibilities in altering hatch window in artificial incubation.

Methods

Layer eggs which were laid on the same day by a single breeder flock and stored for no more than two days started incubation 12 h apart to obtain developmental distinction. The eggs of different initial incubation time were mixed as rows adjacent to rows on day 12 of incubation. During the hatching period (since day 18), hatching time of individual eggs and hatch window were obtained by video recordings. Embryonic development (day 18 and 20) and post-hatch performance up to day 7 were measured.

Results

The manipulation of mixing eggs of different initial incubation time shortened the hatch window of late incubated eggs in the manipulated group by delaying the onset of hatching process, and improved the hatchability. Compared to the control groups, chick embryos or chicks in the egg redistribution group showed no significant difference in embryonic development and post-hatch performance up to day 7.

Discussion

We have demonstrated that eggs that were incubated with advanced eggs performed a narrow spread of hatch with higher hatchability, normal embryonic development as well as unaffected chick quality. This specific manipulation is applicable in industrial poultry production to shorten hatch window and improve the uniformity of chick quality.

Factors affecting fertility, hatchability and chick survivability of Vanaraja birds under intensive rearing in sub-temperate condition

The study was conducted to determine the effect of various factors viz. season, age of hen, egg weight and source of egg on reproductive performance of Vanaraja birds at an altitude of 1300 m at mean sea level in Sikkim. Fertility rate during summer was significantly higher than spring and winter. Fertility rate was significantly higher from 41 to 50 age of week as compared to 51 weeks onwards. Significantly higher fertility rate was observed in medium size egg as compared to other groups. The fertility rate of eggs produced in the farmers field were significantly lower than at farm. Hatchability on fertile egg set was highest during spring followed by summer while it was significantly lower during winter. Significantly higher hatchability was observed in age of 26 to 40 weeks compared to 51–60 and 61–70 weeks of age. Also, significantly higher hatchability was observed in medium size egg group than the other two groups. Chick weight on day of hatching was significantly higher in summer compared to autumn and winter. Egg weight also significantly affects chick weight which was highest in medium size egg. Significantly higher chick’s survivability was recorded in summer, spring and autumn season as compared to winter. Although, season, age of hen, egg weight and source of egg affected the production performance of Vanaraja birds, but it can be reared successfully throughout the year for production purpose.

A 'meta-analysis' of effects of post-hatch food and water deprivation on development, performance and welfare of chickens

A 'meta-analysis' was performed to determine effects of post-hatch food and water deprivation (PHFWD) on chicken development, performance and welfare (including health). Two types of meta-analysis were performed on peer-reviewed scientific publications: a quantitative 'meta-analysis' (MA) and a qualitative analysis (QA). Previously reported effects of PHFWD were quantified in the MA, for variables related to performance, mortality and relative yolk sac weight. The QA counted the number of studies reporting (non-)significant effects when five or more records were available in the data set (i.e. relative heart, liver and pancreas weight; plasma T3, T4 and glucose concentrations; relative duodenum, jejunum and ileum weight; duodenum, jejunum and ileum length; and villus height and crypt depth in duodenum, jejunum and ileum). MA results indicated that 24 hours of PHFWD (i.e. ≥12-36 hours) or more resulted in significantly lower body weights compared to early-fed chickens up to six weeks of age. Body weights and food intake were more reduced as durations of PHFWD (24, 48, 72, ≥84 hours) increased. Feed conversion rate increased in chickens up to 21 and 42 days of age after ≥84 hours PHFWD in comparison with chickens fed earlier. Total mortality at day 42 was higher in chickens after 48 hours PHFWD compared to early fed chickens or chickens after 24 hours PHFWD. First week mortality was higher in chickens after ≥84 hours PHFWD than in early fed chickens. The MA for relative yolk sac weight was inconclusive for PHFWD. The QA for plasma T3, T4 and glucose concentrations indicated mainly short-term decreases in T3 and glucose in PHFWD chickens compared to early fed chickens, and no effects of PHFWD on T4 concentrations. Relative weights of liver, pancreas and heart were lower after PHFWD, but only in the first week of life. A retarded development of gut segments (duodenum, jejunum and ileum) was found in the first week of life, measured as shorter, lower relative weight, and lower villus height and crypt depth. It is concluded that 48 hours (≥36-60 hours) PHFWD leads to lower body weights and higher total mortality in chickens up to six weeks of age, the latter suggesting compromised chicken welfare, but effects of PHFWD on organ development and physiological status appear to be mainly short-term.

Impact of transportation duration on stress responses in day-old chicks from young and old breeders

The aim of this study was to assess the interaction effect of transportation duration and parental age on physiological stress responses and quality in day-old chicks. After hatch, 3240 chicks from either 29-week old (young) or 60-week old (old) broiler breeders were transported for 1.5h (short) or 11h (long). Thereafter, 228 chicks were assessed for quality and blood plasma was assayed for corticosterone (CORT), lactate, glucose, and thiobarbituric acid-reactive substances (TBARS, increased concentrations can indicate oxidative stress). No interaction effects of parental age and transportation duration were found (all P>0.10). Chicks from young breeders showed higher CORT levels (P=0.007) and were of higher quality (Tona method, P<0.001) than those from old breeders. After long transportation, chicks showed increased CORT (P<0.001) and lower TBARS levels (P<0.001) compared to after short transportation. No evidence was provided that long transportation differently affected the quality or stress responses of chicks from breeder flocks of two ages.

Technology and Poultry Welfare

Consideration of animal welfare is essential to address the consumers’ demands and for the long term sustainability of commercial poultry. However, assessing welfare in large poultry flocks, to be able to detect potential welfare risks and to control or minimize its impact is difficult. Current developments in technology and mathematical modelling open new possibilities for real-time automatic monitoring of animal welfare and health. New technological innovations potentially adaptable to commercial poultry are appearing, although their practical implementation is still being defined. In this paper, we review the latest technological developments with potential to be applied to poultry welfare, especially for broiler chickens and laying hens. Some of the examples that are presented and discussed include the following: sensors for farm environmental monitoring, movement, or physiological parameters; imaging technologies such as optical flow to detect gait problems and feather pecking; infrared technologies to evaluate birds’ thermoregulatory features and metabolism changes, that may be indicative of welfare, health and management problems. All these technologies have the potential to be implemented at the commercial level to improve birds’ welfare and to optimize flock management, therefore, improving the efficiency of the system in terms of use of resources and, thus, long term sustainability.

Influence of hatch time and access to feed on intramuscular adipose tissue deposition in broilers

The effect of hatch time and subsequent access to feed on intramuscular adipose tissue deposition was studied in the pectoralis major muscle of male Ross 308 broiler chickens. Based on their hatch time chicks were classified as early (EH), midterm (MH), or late (LH) hatchers, with an average incubation duration of 497.7 h for EH, 508.8 h for MH, and 514.5 h for LH birds. Chicks were provided access to feed either immediately at hatch, or 24 h after the conclusion of the hatch window. Expression of the adipogenic regulatory genes peroxisome proliferator-activated receptor gamma (PPARγ), and stearoyl-CoA desaturase (SCD), were measured at the time of hatch, and zero, one, 4, 7, 28, and 40 d. Intramuscular adipocyte cell width and visualization of adipose tissue deposition was observed at 28 and 40 d. Expression of PPARγ was increased in the pectoralis major of LH birds at the time of hatch, zero, and one d. The expression of PPARγ at one and 7 d, and SCD at 7 d were increased in all birds that received delayed access to feed. At 28 d, adipocyte cell width was increased in LH birds with delayed access to feed, compared to EH and MH birds with delayed access to feed and LH birds with immediate access to feed. At 40 d, adipocyte cell width was increased in all birds that received delayed access to feed. Also at 40 d, there was a trend (P = 0.078) for more extensive intramuscular adipose tissue deposition in LH than EH birds, and in birds with delayed access to feed (P = 0.075). These data indicate delayed access to feed increases intramuscular adipose tissue deposition in the pectoralis major muscle, and suggest that hatch time influences this regulation.

AMPK is involved in the differential neonatal performance of chicks hatching at different time

We have recently reported that the hatching time may be in relation to the distinct neonatal performance of female chicks. The present study was aimed to investigate the potential involvement of AMPK, an energy sensor which plays a pivotal role in energy homeostasis, in the distinct performance of the spread of hatching time model. As a result, hypothalamic AMPKα1 isoform gene expression was significantly higher in the late hatcher as compared to that of their early counterparts, whereas the total and phosphorylated levels of AMPKα subunit did not differ between the three hatchers. The hypothalamic orexigenic NPY and AgRP mRNA levels were higher in the late hatchers as compared to the early, and that of the middle hatchers was at an intermediate level. However, the anorexigenic POMC and CRH was also higher expressed in the late hatchers as compared to the early hatchers. In the liver, AMPKα2 mRNA level and the phosphorylation ratio of AMPKα was significantly lower in the late hatchers, as compared to their early counterparts. The hepatic phosphorylated GS levels of the late and middle hatchers were lower than that of their early counterparts. The expression of hepatic FTO gene of the late hatchers was significantly higher than that of their early and middle counterparts. Taken together, AMPK may play a significant role in the different neonatal performance of the spread of hatching time model. The central and peripheral AMPK in late hatchers exhibited a pattern of higher energy intake and lower energy expenditure, which resulted in a faster post-hatch growth.

Stress Levels, Mortality, Intestinal Morphometry and Histomorphology of Chabro Broiler Birds Subjected to Varying Degrees of Post Hatch Delay in Feeding

BACKGROUND AND OBJECTIVE

Kashmir is a part of Jammu and Kashmir State of India where a large chunk of day old chicks are procured from outside the state and these chicks are transported across a distance of hundreds of kilometers over a period of several days. The long distance transport without any access to feed not only subjects the birds to early life stress but also affects their gut morphological development. Therefore, a study was conducted to evaluate the effect of delayed feeding on stress levels, mortality, intestinal morphometry and histomorphology of chabro broiler chicken.

MATERIALS AND METHODS

A total of 400 day old chabro chicks were randomly divided into 5 groups, each group comprising of four replicates of 20 birds. Chicks allotted to group-1 (G 1) were offered feed at hatchery itself whereas feeding in groups G 2, G 3, G 4 and G 5 were initiated at the farm after the delay of 12, 24, 48 and 72 h, respectively.

RESULTS

The results revealed that the heterophil count showed a steady increase from G 1-G 5 and significantly (p<0.05) higher count was found in G 3, G 4 and G 5 compared to G 1. However, the lymphocyte count showed a steady decrease as delay in feeding increased. H:L ratio followed a regular increase from G 1-G 5 and was significantly (p<0.05) higher in G 3, G 4 and G 5 compared to G 1. An overall mortality of 13% was recorded during the trial and all of it occurred during first 2 weeks. The highest overall mortality of 22.50±3.23% was recorded in group G 5 followed by 17.50±6.61% in G 4. The villus height of duodenum and jejunum was significantly (p<0.05) higher in G 2, G 3, G 4 and G 5 as compared to G 1. Crypt depth and muscular is thickness of duodenum was significantly (p>0.05) lower in G 4 and G 5 compared to G 1.

CONCLUSION

The duration of post hatch feeding delay gradually increased the stress level and mortality of birds and also decreased the length of different segments of small intestine in birds. No adverse effect on histomorphology was observed at the end of trial. Feeding at hatchery itself or feeding during transportation of birds would be a viable strategy to overcome the negative effects of delayed feeding in chicken.

Egg storage duration and hatch window affect gene expression of nutrient transporters and intestine morphological parameters of early hatched broiler chicks

In recent years, researchers have given emphasis on the differences in physiological parameters between early and late hatched chicks within a hatch window. Considering the importance of intestine development in newly hatched chicks, however, changes in gene expression of nutrient transporters in the jejunum of early hatched chicks within a hatch window have not been studied yet. This study was conducted to determine the effects of egg storage duration before incubation and hatch window on intestinal development and expression of PepT1 (H+-dependent peptide transporter) and SGLT1 (sodium-glucose co-transporter) genes in the jejunum of early hatched broiler chicks within a 30 h of hatch window. A total of 1218 eggs obtained from 38-week-old Ross 308 broiler breeder flocks were stored for 3 (ES3) or 14 days (ES14) and incubated at the same conditions. Eggs were checked between 475 and 480 h of incubation and 40 chicks from each egg storage duration were weighed; chick length and rectal temperature were measured. The chicks were sampled to evaluate morphological parameters and PepT1 and SGLT1 expression. The remaining chicks that hatched between 475 and 480 h were placed back in the incubator and the same measurements were conducted with those chicks at the end of hatch window at 510 h of incubation. Chick length, chick dry matter content, rectal temperature and weight of small intestine segments increased, whereas chick weight decreased during the hatch window. The increase in the jejunum length and villus width and area during the hatch window were higher for ES3 than ES14 chicks. PepT1 expression was higher for ES3 chicks compared with ES14. There was a 10.2 and 17.6-fold increase in PepT1 and SGLT1 expression of ES3 chicks at the end of hatch window, whereas it was only 2.3 and 3.3-fold, respectively, for ES14 chicks. These results suggested that egg storage duration affected development of early hatched chicks during 30 h of hatch window. It can be concluded that the ES14 chicks would be less efficiently adapted to absorption process for carbohydrates and protein than those from ES3 at the end of the hatch window.

Effects of hatching time on behavior and weight development of chickens

The length of the embryonic period varies both among and within species and can affect the individual phenotype in many ways, both physiologically and behaviorally. In chickens, the hatch window may last 24–48 hours (up to 10% of the incubation time), and studies have shown that incubation length may affect post-hatch growth and physiology. However, little is known about effects on behavior. We therefore investigated how behavior variation correlates with hatching time in the early life of chickens. We also measured egg weight and egg weight loss in relation to hatching time, as well as post-hatch growth. For females, there was a negative correlation between hatch time and body weight from day 4 and throughout the experiment. For males, such a correlation was only observed when testing all hatched males up until day 10. The birds were exposed to a number of behavioral tests, and a principal components analysis was performed on the variables, resulting in four components. For the largest component, termed “Passivity”, a tendency of a difference was found between early and middle male hatchers. Furthermore, a significant difference between early and middle male hatchers was found in the second component, termed “Response to novelty”. In a spatial learning test, late hatchers tended to learn slower. The behavior of females was not significantly affected by hatching time in any of these tests. This study is among the first to demonstrate a link between time of hatching and early behavior in a precocial species like the chicken, and may help shedding light on the evolutionary trade-offs between incubation length and post-hatch traits. The results may also be relevant from a perspective of stress coping and therefore also for animal welfare and productivity in the chicken industry. The mechanisms linking hatching time with post-hatch phenotype remain to be investigated.

Perinatal broiler physiology between hatching and chick collection in 2 hatching systems

Little is known about physiological responses of early- versus late-hatching chicks to early posthatch conditions in broiler practice. We investigated effects of hatching time on perinatal broiler physiology in 2 hatching systems, differing in conditions: a conventional hatcher, where chicks are deprived of feed and water between hatching and the moment of chick pulling (d E21.5), and a patio system, in which the hatching and brooding phase are combined, and chicks have immediate posthatch feed and water access. Climate conditions in patio also differ with about 3°C lower temperature and 20% lower RH compared with conventional hatchers. At E18, fertile eggs were transferred to either a hatcher or the patio until the end of incubation. From each system, 50 newly hatched chicks were collected at 3 hatching times: at 468 h (early), 483 h (midterm), and 498 h (late) of incubation, of which 25 chicks were decapitated for analyses of physiological parameters. The other 25 chicks were returned to the hatching system for analyses after 515 h of incubation (E21.5). At hatch, weights of the heart, lungs, stomach, and intestine increased with hatching time, concurrent with a decrease in residual yolk weight, regardless of hatching system, and indicating that later hatching chicks are more matured. Weights of the heart, liver, stomach, and intestines were lower in hatcher than in patio chicks. Between hatch and E21.5, residual yolk weight decreased, whereas organ weights increased in both fasted hatcher and fed patio chicks, but at a higher rate in the latter. At E21.5, plasma glucose and triiodothyronine had increased with time after hatch in patio chicks, whereas levels were similar among hatching times and lower in hatcher chicks. Early feed and water access seems to enable early hatching chicks to compensate for their apparent disadvantage in development at hatching, whereas chicks subjected to fasting show metabolic adaptations to preserve nutrients. Chick physiology at chick pulling time was shown to vary with time after hatching and posthatch conditions, especially feed access.

Physiological relationships of the early posthatch performance of broilers to their embryo and eggshell characteristics

Relationships between physiological parameters of early posthatch chicks with their corresponding egg and embryo parameters were examined in progeny of young broiler breeders. Four hundred and 80 broiler hatching eggs that were obtained from a 29-wk-old Ross 308 breeder flock were incubated on 8 replicate tray levels of an incubator until hatch. Between 10.5 and 18.5 d of incubation, internal (T(emb)) and external (T(ext)) egg temperatures were recorded twice daily using temperature transponders. Beginning at 18.5 d, the eggs were individually monitored for hatch every 12 h. Average T(emb), T(ext), and average daily incubational egg weight loss (EWL) for the 10.5- to 18.5-d incubation period were used to calculate eggshell water vapor conductance (G(H2O)), specific G(H2O) (g(H2O); G(H2O) adjusted to 100 g of set egg weight basis), and a G(H2O) constant (K(H2O)) for each egg. Chicks were grown out for 10 d in pens of a single battery brooder. In each pen, on d 3 posthatch, carcasses, yolk sac, liver, and pipping muscle samples were collected from at least 2 chicks that hatched from eggs implanted with transponders for determination of their relative weights and moisture concentrations. Livers and pipping muscles were also analyzed for glucose, glycogen, fat, and protein concentrations. Yolk sac weight as a percentage of chick BW (YW) and its moisture concentration (YSM) were positively correlated with T(emb). Egg g(H2O) was positively correlated with chick carcass moisture concentration and its relative weight as a percentage of set egg weight, but it was negatively correlated with YW. The positive functional relationship between T(emb) and incubation length may be mediated via their common positive relationships to YSM. A negative correlation was observed between percentage EWL and relative BW on d 0 and 0.5 posthatch for chicks hatched from unimplanted eggs. The results suggest that a higher g(H2O) results in an increased metabolism of the broiler embryo, which subsequently increases growth and yolk sac absorption in broiler chicks through 3 d posthatch.

Investigating the Effect of In Ovo Injection of Silver Nanoparticles on Fat Uptake and Development in Broiler and Layer Hatchlings

Silver nanoparticles (AgNano) as carrier of available oxygen (O2) and with high surface reactivity may increase O2consumption, enhance fat uptake (FU), and stimulate growth and development. The objective was to investigate the effects of in ovo injection of AgNano on the metabolic rate (O2consumption, CO2production, and heat production, HP), fat uptake, and the development of broiler and layer hatchlings. AgNano concentrations (50, 75, and 100 mg/kg) were injected in ovo at day 1 of incubation to different breeds of broiler and layer chicken embryos. Oxygen consumption and subsequently FU did not increase linearly following AgNano treatment. FU was lower in hatchlings treated with 50 and 100 mg AgNano/kg, but surprisingly not in hatchlings treated with 75 mg AgNano/kg. Interestingly, the difference in FU between treatments was not reflected in hatchling development. The results indicated that AgNano affected metabolic rate and FU; however, it did not influence the development of hatchlings. This suggests that in ovo injection of AgNano reduces the need to use yolk fat as an energy source during embryonic development and consequently the remaining fat in the residual yolk sac may provide a potent source of nutritional reserves for chicks of few days after hatching.