Incubation and hatching conditions of laying hen chicks explain a large part of the stress effects from commercial large-scale hatcheries

A conventional hatchery vs "on-farm" hatching of broiler chickens in terms of microbiological and microclimatic conditions

"On-farm hatching" is one of the proposed alternatives to conventional hatchery-hatching. This solution reduces distress and improves the welfare of the chicks around the hatching period. Therefore, it seemed interesting to compare conventional hatchery and "on-farm" hatching in terms of microbiological and microclimatic conditions. Hatching eggs (Ross 308) were incubated in a commercial hatchery. The control group (HH, 683 eggs) hatched in a conventional hatcher, while the other eggs were transported into the experimental chicken-hall for on-farm hatching, and set in pens directly on litter (OL, 667 eggs) or plastic trays (OT, 678 eggs). One-day-old chicks were also placed in the experimental hall. Microclimatic parameters were controlled every 12 h. The microbiological status of the surface of the eggshells and the litter was assessed based on the total number of aerobic mesophilic microorganisms and also the selected individual genus/species of bacteria. The hatchability of HH was 96.4% in comparison to 93.9% and 95.8% for OL and OT, respectively (P > 0.05). On the other hand, 2.1% of the HH chicks were found injured/dead, while only 0.2-0.3% of the on-farm groups were. The total number of aerobic mesophilic microflora on the surface of as-hatched shells was 4.93 ± 0.629 log CFU/g in HH, while only 1.14 ± 0.995 and 1.93 ± 1.709 log CFU/g in OL and OT, respectively (P < 0.001). Similarly, the total count of bacteria in the litter in the on-farm hatched pens was 1.9-fold lower than in pens set with HH chicks (P < 0.001). In summary, on-farm hatching results in hatchability that is no worse than in a conventional hatcher, while the microbiological status of as-hatched eggshells and litter is significantly better. Therefore, on-farm hatching seems to provide appropriate environmental conditions for newly hatched chicks and poses no epizootic risk.

Commercial hatchery practices have long-lasting effects on laying hens' spatial behaviour and health

The commercial hatchery process is globally standardized and exposes billions of day-old layer chicks to stress every year. By alleviating this early stress, on-farm hatching is thought to improve animal welfare, yet little is known about its effects throughout production. This study compared welfare indicators and spatial behaviours during the laying period of hens hatched in an on-farm environment (OFH) to those hatched in a commercial hatchery and transferred at one day-old to a rearing barn (STAN). In particular, we assessed how OFH and TRAN hens differed in space-use and movement behaviours following the transfer to the laying barn at 17 weeks of age, a similar stressor encountered by STAN hens early in life, and determined whether effects aligned more with the 'silver-spoon' or 'environmental matching' hypothesis. We found that for the first three months post-transfer into the laying barn, OFH hens, on average, transitioned less between the aviary's tiers and spent less time on the littered floor. Because OFH hens became behaviourally more similar to STAN hens over time, these results suggest that OFH hens required a prolonged period to establish their daily behavioural patterns. Furthermore, OFH hens had more severe keel bone fractures throughout the laying period but similar feather damage and body mass to STAN hens. No differences were found in hen mortality or the number of eggs per live hen. These findings support the environmental matching hypothesis and suggest that early-life stressors may have prepared hens for later-life stressors, underscoring the importance of both early-life and adult environments in enhancing animal welfare throughout production.

New Behavioral Handling Test Reveals Temperament Differences in Native Japanese Chickens

It is well known in the poultry industry that fear and stress experienced during the handling of day-old chicks in commercial hatcheries can have long-lasting effects on their behavior later in life. These hatchery-related stresses are more intense and complex than those encountered in traditional behavioral tests. Consequently, a single behavioral test may not be sufficient to measure hatchery stresses and chicken temperament. In this study, we developed a new behavioral handling test for day-old chickens, which incorporated concepts from established behavioral tests used with both young and adult birds. The new test assessed 10 behavioral traits, including vocalization frequency and responses to human interaction. It was conducted on 96 two-day-old chicks from seven breeds of native Japanese and Western chickens. The results of the principal component analysis classified chicken temperaments into three distinct categories: bustle, aggression, and timidity. Using these categories, the seven breeds were classified into five groups, each with distinct temperaments. This study highlights the reliability and value of the new handling test in characterizing the temperaments of various chicken breeds and provides insights into the complex behaviors of chickens.

Commercial hatchery processing may affect susceptibility to stress in laying hens

Directly upon hatching, laying hen chicks are exposed to multiple stressful events during large-scale hatchery processing, which may affect their later coping abilities. Commercial hatchery chicks (HC) were compared to chicks that were incubated and hatched simultaneously under calm conditions (CC). After being raised under similar, non-stressful conditions for 36 days, all chicks were exposed to a series of stressors: transportation and introduction into a novel environment followed by a regrouping event in order to characterize long-lasting consequences of hatchery treatment. Tonic immobility, corticosterone levels, and peripheral body temperature were used to assess reactions to the stress events. Tonic immobility was not affected by treatment but was significantly reduced in CC after transport. Corticosterone levels did not differ between treatments when assessed two days before and two days after regrouping. Comb temperature was significantly higher in HC following regrouping, indicating stress-induced hyperthermia. Furthermore, comb temperature dropped more following blood sampling in HC than in CC, indicating a stronger autonomic response to acute stress. In conclusion, the results suggest possible long-term negative effects of commercial hatchery processing, compared to hatching under silent and less stressful conditions, on the coping ability of laying hens to later stressful experiences.

Potential Implication of in ovo Feeding of Phytogenics in Poultry Production

Hatchery's goals include maximizing revenue by achieving high hatchability with day-old birds of excellent quality. The advancement of technology has benefited the poultry sector since breeding and genetics technology have increased the rates of meat maturation in developing birds in a short period of time. Excessive use of in-feed antibiotics has been shown in studies to increase the chance of resistance to human infections. Bacterial resistance and antibiotic residues in animal products raised concerns about using antibiotics as growth promoters, eventually leading to a prohibition on using in-feed antibiotics in most industrialized nations. In ovo technology is a novel method for delivering bioactive chemicals to developing avian embryos. In ovo feeding technologies may provide additional nutrients to the embryos before hatching. The introduction of bioactive compounds has the potential to assist in decreasing and eventually eliminating the problems associated with traditional antibiotic delivery in chicken production. Phytobiotics were advocated as an alternative by researchers and dietitians. So far, several studies have been conducted on the use of phytogenic feed additives in poultry and swine feeding. They have primarily demonstrated that phytobiotics possess antibacterial, antioxidant, anti-inflammatory, and growth-stimulating properties. The antioxidant effect of phytobiotics can improve the stability of animal feed and increase the quality and storage duration of animal products. In general, the existing documentation indicates that phytobiotics improve poultry performance. To effectively and efficiently use the in ovo technique in poultry production and advance research in this area, it is important to have a thorough understanding of its potential as a means of nutrient delivery during the critical stage of incubation, its effects on hatching events and posthatch performance, and the challenges associated with its use. Overall, this review suggests that in ovo feeding of phytobiotics has the potential to improve the antioxidant status and performance of chickens.

Poultry health constraints in smallholder village poultry systems in Northern Ghana and Central Tanzania

Introduction

Smallholder poultry production is a major contributor to food security and rural livelihoods in low-and middle-income countries. However, infectious diseases limit improvements to smallholder poultry production and performance of the sector in general. Infectious diseases of poultry, especially viral diseases, have major impacts on the health and productivity of flocks and account for significant morbidities and mortalities of birds each year.

Methods

This study utilized participatory epidemiology approaches to better understand the poultry health constraints and challenges faced by smallholder poultry producers in village poultry systems in Northern Ghana and Central Tanzania.

Results

The results show dominance of small-scale semi-intensive and extensive scavenging poultry production systems in the study areas. Newcastle disease ranked as the highest cause of morbidity and mortality in chickens in the two countries. The disease occurred mainly during the months coinciding with the dry season in both countries. Other health challenges among poultry flocks included worm infestation, fowl pox, coryza, and coccidiosis. Producers, especially in rural locations, had poor access to veterinary services and critical inputs necessary for poultry production. In the Northern region of Ghana, producers lacked definitive diagnoses for sick poultry due to a shortage of veterinary personnel and diagnostic laboratories.

Discussion

These challenges point to the need for increased investment in poultry disease control and prevention programs, particularly in rural areas. Interventions focused on expansion of veterinary and agricultural extension services and diagnostic laboratory capacity in rural areas and increased gender-sensitive training to enhance smallholder knowledge in poultry husbandry and disease prevention measures will support the development of the smallholder village poultry systems. Tapping into the diverse genetic reservoir of local chicken ecotypes with enhanced resistance to Newcastle disease through genomic selection, coupled with models for enhancing ND vaccination supply and use in the rural areas are potential future avenues for addressing ND constraints to production.

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.

Effect of prenatal different auditory environment on learning ability and fearfulness in chicks

Objective

Early environmental enrichment in life can improve cognition in animals. The effect of prenatal auditory stimulation on learning ability and fear level in chick embryos remained unexplored. Therefore, this study investigated the effect of prenatal auditory stimulation on the learning ability and fear level of chicks.

Methods

A total of 450 fertilized eggs were randomly divided into 5 groups, including control group (C), low-sound intensity music group (LM), low-sound intensity noise group (LN), high-sound intensity noise group (HN) and high-sound intensity music group (HM). From the 10th day of embryonic development until hatching, group LM and group LN received 65 to 75 dB of music and noise stimulation. Group HN and group HM received 85 to 95 dB of noise and music stimulation, and group C received no additional sound. At the end of incubation, the one-trial passive avoidance learning (PAL) task and tonic immobility (TI) tests were carried out, and the serum corticosterone (CORT) and serotonin (5-HT) concentrations were determined.

Results

The results showed that compared with the group C, 65 to 75 dB of music and noise stimulation did not affect the PAL avoidance rate (p>0.05), duration of TI (p>0.05) and the concentration of CORT (p>0.05) and 5-HT (p>0.05) in chicks. However, 85 to 95 dB of music and noise stimulation could reduce duration of TI (p<0.05) and the concentration of CORT (p<0.05), but no significant effect was observed on the concentration of 5-HT (p>0.05) and PAL avoidance rate (p>0.05).

Conclusion

Therefore, the prenatal auditory stimulation of 85 to 95 dB can effectively reduce the fear level of chicks while it does not affect the learning ability.

Effects of stress during commercial hatching on growth, egg production and feather pecking in laying hens

Every year, billions of egg layer chicks around the world are hatched under highly stressful, industrial circumstances. Here, it is investigated how the stressful procedure in the commercial hatchery, including incubation, hatching, processing, and transport affects the chicks with regards to traits relevant for the egg production industry. These traits were compared to those of a control group hatched in a small incubator and handled gently och quietly in a quiet room without any processing and transport. The chicks were weighed at hatch and at eight additional time points: 4 days, 1 week (w), 2 w, 3 w, 5 w, 8 w, 20 w and 25 w of age. Feather pecking was studied at 15 w of age and damages to the feathers and injuries on the comb and wattle were assessed at 25 w of age. From 19 w of age, eggs were collected on three days per week, counted and weighed. Chicks from a commercial hatchery had a lower hatch weight than control chicks (p<0.001). At 20 w of age, the weight of the commercial hatched chicks was still numerically lower, although this did not reach statistical significance. Commercially hatched chicks tended to show more feather pecking behaviour at 15 w of age compared to control chicks (p<0.1), although feather condition at 25 w of age showed the opposite pattern. Regarding production, commercially hatched chickens laid fewer (p<0.05) and smaller (p<0.05) eggs than chicks hatched and handled under calm circumstances. From this experiment, it is concluded that the stressful experience in the commercial hatchery has an overall negative effect on traits relevant for the industry.

Serum clinical biochemical markers of Hy-Line W-36 laying hens under the influence of increased stocking densities in cages of multilevel batteries

Today, the organism of hens is constantly exposed to numerous technological stressors in the conditions of industrial poultry farming, the least studied of which are long-term, which can cause the development of chronic stress. One of such stressors is the increased stocking density of hens, which is also a way of saving resources in egg poultry and is often used by producers to obtain more eggs per 1 m2 of poultry area. The aim of this study was to examine the effect of overcrowding, as a factor of chronic stress development, on the body of hens of a modern high-performance cross, which is necessary to select the best ways to keep them. Four groups of hens were formed for this purpose, which were kept at different stocking densities, according to European standards, Ukrainian standards and with increasing overcrowding. In this way, the gradually increasing intensity of the technological stressor was modeled. Long-term keeping of laying hens at high stocking density did not affect the content in the serum of total protein, albumin, urea and cholesterol, which were within the physiological norm. It was found that the increase in the stocking density of hens to Ukrainian standards, compared to the European, was accompanied by an increase in the activity of lactate dehydrogenase in the serum of their blood. With an increase in stocking density above European and Ukrainian standards, namely to 25.3 birds/m2, there was an increase in the activity of three enzymes – lactate dehydrogenase, aspartate aminotransferase and gamma-glutamyltransferase. It is proved that further overcompaction of hens to 26.7 birds/m2 is accompanied by an increase in serum glucose, creatinine, as well as a decrease in the ratio of calcium and phosphorus, which was confirmed by an increase in alkaline phosphatase activity. Also, increased activity of aspartate aminotransferase, lactate dehydrogenase and gamma-glutamyltransferase was observed. Thus, the main effects of chronic stress caused by prolonged keeping of hens at high stocking densities are reflected in the biochemical parameters of their serum, namely in the increase of glucose, creatinine, enzyme activity, as well as the violation of the ratio of calcium and phosphorus.

Stress during Commercial Hatchery Processing Induces Long-Time Negative Cognitive Judgement Bias in Chickens

Simple Summary

Worldwide, billions of laying hen chicks are incubated, hatched and processed in industrial hatcheries every year. When exposed to stress, hormones are incorporated in the feathers of the birds. Here, we measured levels of the stress hormone corticosterone to investigate possible stress during the incubation. Further, animals can perceive their environment either in a positive (optimistic) or a negative (pessimistic) way. We investigated how the early hatchery experiences affects “optimism” and “pessimism”. Commercially hatched chicks were exposed to a positive cue, an aversive cue, and ambiguous cues, in order to evaluate the cognitive welfare state of the animals. These chicks were compared to a group of non-stressed animals. Commercially incubated chicks did not have elevated levels of feather corticosterone, which implies that the main part of the stress effects from the hatchery originates from the period around hatch. Latencies to approach ambiguous cues were longer for the stressed chicks, i.e., these showed a more pessimistic-like behaviour. We conclude that the main part of the stress effects in commercially hatched chicks originates in the period around hatch, and further, that these birds show lasting levels of increased pessimism. This strongly indicates a long-time poorer welfare state for the animals.

Abstract

Worldwide, billions of laying hen chicks are incubated and processed under highly industrialised circumstances every year, which, as we have previously shown, has long-lasting effects. Here, we measured corticosterone incorporated in down feathers to investigate possible stress during the incubation and showed that commercially incubated chicks did not have elevated levels of feather corticosterone, which implies that the main part of the stress effects from hatchery originates from the perinatal period and the handling immediately post-hatch. Further, we investigated how the early hatchery stress affects the chicks’ cognitive welfare state, i.e., “optimism” and “pessimism”. We exposed commercially hatched chickens to a positive cue, an aversive cue and ambiguous cues. The birds were tested at 1 and 10 w of age and the behaviour was compared with that of non-stressed chicks. Latencies to approach ambiguous cues were longer for the stressed chicks, both at 1 (p = 0.008) and at 10 (p = 0.020) weeks of age, i.e., these showed a more pessimistic-like behaviour. We conclude that the main part of the stress effects in commercially hatched chicks originates in the perinatal period, and further, that these birds show lasting levels of increased pessimism. This strongly indicates a long-time poorer welfare state for the animals.