Use of dynamic and rewarding environmental enrichment to alleviate feather pecking in non-cage laying hens

The Influence of Cecal Microbiota Transplantation on Chicken Injurious Behavior: Perspective in Human Neuropsychiatric Research

Numerous studies have evidenced that neuropsychiatric disorders (mental illness and emotional disturbances) with aggression (or violence) pose a significant challenge to public health and contribute to a substantial economic burden worldwide. Especially, social disorganization (or social inequality) associated with childhood adversity has long-lasting effects on mental health, increasing the risk of developing neuropsychiatric disorders. Intestinal bacteria, functionally as an endocrine organ and a second brain, release various immunomodulators and bioactive compounds directly or indirectly regulating a host's physiological and behavioral homeostasis. Under various social challenges, stress-induced dysbiosis increases gut permeability causes serial reactions: releasing neurotoxic compounds, leading to neuroinflammation and neuronal injury, and eventually neuropsychiatric disorders associated with aggressive, violent, or impulsive behavior in humans and various animals via a complex bidirectional communication of the microbiota-gut-brain (MGB) axis. The dysregulation of the MGB axis has also been recognized as one of the reasons for the prevalence of social stress-induced injurious behaviors (feather pecking, aggression, and cannibalistic pecking) in chickens. However, existing knowledge of preventing and treating these disorders in both humans and chickens is not well understood. In previous studies, we developed a non-mammal model in an abnormal behavioral investigation by rationalizing the effects of gut microbiota on injurious behaviors in chickens. Based on our earlier success, the perspective article outlines the possibility of reducing stress-induced injurious behaviors in chickens through modifying gut microbiota via cecal microbiota transplantation, with the potential for providing a biotherapeutic rationale for preventing injurious behaviors among individuals with mental disorders via restoring gut microbiota diversity and function.

Cecal microbiota transplantation: unique influence of cecal microbiota from divergently selected inbred donor lines on cecal microbial profile, serotonergic activity, and aggressive behavior of recipient chickens

BACKGROUND

Accumulating evidence from human trials and rodent studies has indicated that modulation of gut microbiota affects host physiological homeostasis and behavioral characteristics. Similarly, alterations in gut microbiota could be a feasible strategy for reducing aggressive behavior and improving health in chickens. The study was conducted to determine the effects of early-life cecal microbiota transplantation (CMT) on cecal microbial composition, brain serotonergic activity, and aggressive behavior of recipient chickens.

METHODS

Chicken lines 6₃ and 7₂ with nonaggressive and aggressive behavior, respectively, were used as donors and a commercial strain Dekalb XL was used as recipients for CMT. Eighty-four 1-d-old male chicks were randomly assigned to 1 of 3 treatments with 7 cages per treatment and 4 chickens per cage (n = 7): saline (control, CTRL), cecal solution of line 6₃ (6₃-CMT), and cecal solution of line 7₂ (7₂-CMT). Transplantation was conducted via oral gavage once daily from d 1 to 10, and then boosted once weekly from week 3 to 5. At weeks 5 and 16, home-cage behavior was recorded, and chickens with similar body weights were assigned to paired aggression tests between the treatments. Samples of blood, brain, and cecal content were collected from the post-tested chickens to detect CMT-induced biological and microbiota changes.

RESULTS

6₃-CMT chickens displayed less aggressive behavior with a higher hypothalamic serotonergic activity at week 5. Correspondingly, two amplicon sequence variants (ASVs) belonging to Lachnospiraceae and one Ruminococcaceae UCG-005 ASV were positively correlated with the levels of brain tryptophan and serotonin, respectively. 7₂-CMT chickens had lower levels of brain norepinephrine and dopamine at week 5 with higher levels of plasma serotonin and tryptophan at week 16. ASVs belonging to Mollicutes RF39 and GCA-900066225 in 7₂-CMT chickens were negatively correlated with the brain 5-hydroxyindoleacetic acid (5-HIAA) at week 5, and one Bacteroides ASV was negatively correlated with plasma serotonin at week 16.

CONCLUSION

Results indicate that CMT at an early age could regulate aggressive behavior via modulating the cecal microbial composition, together with central serotonergic and catecholaminergic systems in recipient chickens. The selected CMT could be a novel strategy for reducing aggressive behavior through regulating signaling along the microbiota-gut-brain axis.

Farm Environmental Enrichments Improve the Welfare of Layer Chicks and Pullets: A Comprehensive Review

Currently, cage housing is regarded as a global mainstream production system for laying hens. However, limited living space and confinement of birds in cages cause welfare and health problems, such as feather pecking, osteoporosis, obesity, and premature aging. Many studies have been conducted to alleviate layer welfare problems by providing farm environmental enrichments such as litter, sand, alfalfa bales, chick papers, pecking stones, pecking strings, perches, slopes, elevated platforms, aviaries and outdoor access with a trend towards complex enrichments. The provision of appropriate enrichments continuously attracts layers towards pecking, foraging, dust bathing, and locomotion, thereby giving lifelong benefits to laying hens. Hence, raising chicks and pullets under such conditions may reduce feather and skin damage, as well as accumulation of abdominal fat, and improve several biological features such as health, productivity, quality products, and docility of laying hens. Therefore, providing enrichment during the first few days of the layer’s life without any interruption is crucial. In addition, due to different farm conditions, environmental enrichment should be managed by well-trained farm staff. For example, in preventing feather pecking among the birds, litter materials for foraging are superior to dust bath materials or new items. However, a limited supply of litter creates competition and challenges among birds. Therefore, providing farm environmental enrichment for layers requires proper handling, especially in commercial layer farms. Hence, improving the welfare of chicks and pullets through optimizing on-farm environmental enrichments is essential for production systems practicing cage housing.

Welfare issues and potential solutions for laying hens in free range and organic production systems: A review based on literature and interviews

In free-range and organic production systems, hens can make choices according to their needs and desires, which is in accordance with welfare definitions. Nonetheless, health and behavioral problems are also encountered in these systems. The aim of this article was to identify welfare challenges observed in these production systems in the EU and the most promising solutions to overcome these challenges. It is based on a review of published literature and research projects complemented by interviews with experts. We selected EU specific information for welfare problems, however, the selected literature regarding solutions is global. Free range use may increase the risk of infection by some bacteria, viruses and parasites. Preventive methods include avoiding contamination thanks to biosecurity measures and strengthening animals' natural defenses against these diseases which can be based on nutritional means with new diet components such as insect-derived products, probiotics and prebiotics. Phytotherapy and aromatherapy can be used as preventive and curative medicine and vaccines as alternatives to antibiotics and pesticides. Bone quality in pullets and hens prevents keel deviations and is favored by exercise in the outdoor range. Free range use also lead to higher exposure to variable weather conditions and predators, therefore shadow, fences and guard animals can be used to prevent heat stress and predation respectively. Granting a free range provides opportunities for the expression of many behaviors and yet many hens usually stay close to the house. Providing the birds with trees, shelters or attractive plants can increase range use. Small flock sizes, early experiences of enrichment and personality traits have also been found to enhance range use. Severe feather pecking can occur in free range production systems, although flocks using the outdoor area have better plumage than indoors. While many prevention strategies are facilitated in free range systems, the influence of genetics, prenatal and nutritional factors in free range hens still need to be investigated. This review provides information about practices that have been tested or still need to be explored and this information can be used by stakeholders and researchers to help them evaluate the applicability of these solutions for welfare improvement.

Bird Welfare in Zoos and Aquariums: General Insights across Industries

Animal welfare is a priority across accredited zoological institutions; however, historically, research has been prioritized for mammals. Bird-focused studies accounted for less than 10% of welfare research in zoos and aquariums over the last ten years. Due to the lack of scientific publications on bird welfare, zoo scientists and animal practitioners can look to other industries such as agriculture, laboratories, and companion animal research for insight. This qualitative review highlights findings across industries to inform animal care staff and scientists on the welfare needs of birds within zoos and aquariums. Specifically, the review includes an overview of research on different topics and a summary of key findings across nine resources that affect bird welfare. We also highlight areas where additional research is necessary. Future welfare research in zoos and aquariums should prioritize studies that consider a diversity of bird species across topics and work to identify animal-based measures with empirical evidence. Moving forward, research from other industries can help develop innovative research on bird welfare within zoos and aquariums.

Effect of Providing Environmental Enrichment into Aviary House on the Welfare of Laying Hens

This study aimed to determine the effects of providing environmental enrichment materials—pumice stone and alfalfa hay—to laying hens in the aviary system. A total of 2196 40-week-old Hy-Line Brown laying hens were randomly allotted to three treatment groups: (1) no enrichment (control; CON), (2) enrichment with pumice stone (PS), and (3) enrichment with alfalfa hay (HAY). Each treatment comprised four replicates of 183 hens each, and four of the same materials were provided per replicate. The experiment lasted for 26 weeks. Feed and water were provided ad libitum. As a result, the PS and HAY groups demonstrated increased egg production (p < 0.001). The HAY group showed a reduced rate of mislaid eggs (p < 0.01) and produced low egg weight and pale-yellow yolk (p < 0.05). Both enrichment materials decreased blood creatinine (CRE) or lactate dehydrogenase (LDH) in the blood and resulted in a significantly lower corticosterone (CORT) level (p < 0.05). However, the feather condition scores for the laying hens were similar across all treatments (p > 0.05). In summary, although pumice stone and alfalfa hay are effective in alleviating stress and improving the production of laying hens, additional environmental improvement studies are needed to contribute to reducing pecking behaviors in poultry farming.

A Place to Be? Use of Winter Gardens with and without Automatic Enrichment Devices by Laying Hens

Since the abolition of beak trimming in laying hens in Germany, the importance of adequate enrichment material to help reduce feather pecking and cannibalism has grown. Here we tested an automatic enrichment device dosing grain via rough-coated pecking plates (PPs) on an organic farm, comparing its offer in four winter gardens (WGs). Winter garden (WG) 1 served as the control area without an automatic enrichment device, while WGs 2–4 offered different quantities of PPs, with WG 2 offering double the amount of PPs as WGs 3 and 4. The number of laying hens (Lohmann Brown Lite) per m² and close to the enrichment device (one hen‘s body length around) was determined using photo records. The usage behavior of the hens differed in the four WGs and with the animals’ age. Over the whole husbandry period (60 weeks), on average, 1.48 hens/m² were detected in the control area (WG 1), and a mean of 2.27 hens/m² in the enriched WGs. Compared to WG 1, the number of hens per m² was higher in WG 2 (2.43 hens/m²) and WG 3 (2.59 hens/m²) (p < 0.05), but similar in WG 4 (1.79 hens/m²). At the end of the husbandry period, fewer animals (mean of all WGs: 1.43 hens/m²) used the WGs than from beginning to the middle of the laying period (mean of all WGs: 2.05–2.15 hens/m²; p < 0.05). Our data indicate that the automatic enrichment device positively influences the animals’ use of the WG.

Environmental enrichment in commercial flocks of aviary housed laying hens: relationship with plumage condition and fearfulness

Management strategies can have positive effects on laying hen welfare, including prevention of damaging behavior, aggression, and fear, particularly by using environmental enrichment (EE). However, few studies have investigated the effects of the provision of EE in commercial aviary flocks. This knowledge gap is particularly significant considering the increasing numbers of non-beak trimmed hens worldwide kept in aviaries. The aim of this study was to survey and investigate the relationship between commercially applied EE and plumage condition and fearfulness in Norwegian flocks of loose-housed laying hens. Forty-five indoor multi-tiered aviary-system flocks of laying hens from across Norway were visited at the end of lay (range: 70–76 wk of age). The flocks consisted of either Lohmann LSL (n = 30) or Dekalb White (n = 15) non–beak-trimmed hens. During the visit, the researchers collected data on the farmers’ use of the following five types of enrichment: pecking stones, gravel, oyster shells, grains scattered in the litter, and “toys”. Feather loss was assessed individually in approximately 50 hens per flock and scores were awarded using a 3-point scale (0–2) for each of the following body parts: head, back/wings, breast, and tail. Finally, a novel object test was performed in 4 different locations in each house. The results showed that damage to the tail feathers was correlated positively to the first age of provision of toys (Pearson correlation coefficient = 0.41; P = 0.051) and negatively to the amounts of gravel stones provided (Pearson correlation coefficient = −0.43, P = 0.02). No other associations between the welfare indicators and the provision of EE objects were found, likely because of the low variation of enrichment provision. The present study showed that the provision of EE objects such as toys and gravel stones can have significant benefits to the condition of laying hen plumage. This study also adds to the body of literature supporting the importance of early life experiences on the behavioral development of laying hens and on their welfare at older ages.

The Sequential Behavior Pattern Analysis of Broiler Chickens Exposed to Heat Stress

Broiler productivity is dependent on a range of variables; among them, the rearing environment is a significant factor for proper well-being and productivity. Behavior indicates the bird’s initial response to an adverse environment and is capable of providing an indicator of well-being in real-time. The present study aims to identify and characterize the sequential pattern of broilers’ behavior when exposed to thermoneutral conditions (TNZ) and thermal stress (HS) by constant heat. The research was carried out in a climatic chamber with 18 broilers under thermoneutral conditions and heat stress for three consecutive days (at three different ages). The behavior database was first analyzed using one-way ANOVA, Tukey test by age, and Boxplot graphs, and then the sequence of the behaviors was evaluated using the generalized sequential pattern (GSP) algorithm. We were able to predict behavioral patterns at the different temperatures assessed from the behavioral sequences. Birds in HS were prostrate, identified by the shorter behavioral sequence, such as the {Lying down, Eating} pattern, unlike TNZ ({Lying down, Walking, Drinking, Walking, Lying down}), which indicates a tendency to increase behaviors (feeding and locomotor activities) that guarantee the better welfare of the birds. The sequence of behaviors ‘Lying down’ followed by ‘Lying laterally’ occurred only in HS, which represents a stressful thermal environment for the bird. Using the pattern mining sequences approach, we were able to identify temporal relationships between thermal stress and broiler behavior, confirming the need for further studies on the use of temporal behavior sequences in environmental controllers.

The Effect of the Type of Non-Caged Housing System, Genotype and Age on the Behaviour of Laying Hens

This study investigated the welfare of laying hens in different non-caged housing systems, namely a deep-litter barn system (BS), a free-range system (FRS) and an organic system (OS). The study was conducted on 270 hens of a native breed Green-legged Partridge (Z-11) and 270 Hy-Line Brown hybrids. Visual scans were performed to record behaviour of hens. Hens were housed in groups of 30 and observed over the course of one day at 20, 36 and 56 weeks of age. Dustbathing, scratching, wing stretching, wing flapping and preening were recorded as comfort behaviours. Pecking, fighting, threatening and chasing were recorded as agonistic behaviours. The percentage of run use was higher in native hens than in commercial hens (p < 0.05). The proportion of hens exhibiting comfort behaviours housed in the FRS and OS was similar but over twice as high as in the BS (p < 0.05). In the FRS and OS, the percentage of hens displaying comfort behaviours increased with age (p < 0.05). In all the production systems, the percentage of birds displaying comfort behaviours was higher in native breed hens than in commercial breeds (p < 0.05). In the BS, the higher proportion of hens displaying an agonistic behaviour was seen more in commercial breed than in the native breed hens (p < 0.05). The percentage of birds displaying an agonistic behaviour declined with hen age, both in commercial and native breed hens.

A meta-analysis on the effect of environmental enrichment on feather pecking and feather damage in laying hens

Feather pecking (FP) is a significant issue in laying hens, which impacts societal acceptance of poultry farming, farm productivity, and bird welfare. Environmental enrichment-modifications of the environment to stimulate biological functioning and psychological well-being of animals-is one management strategy farmers can use to mitigate FP. However, inconsistent results of environmental enrichment are reported across studies questioning its value. A meta-analysis was used to determine the effect of environmental enrichment on FP and feather damage (FD) in laying hens. A systematic review of published literature from 4 databases resulted in 23 publications that met inclusion criteria. Feather pecking and FD outcomes were standardized between studies using different scoring systems. Driving variables included the presence of enrichment, production period when the enrichment started, housing type, beak trimming, bird strain, and age of the birds when FP and FD was measured. Considering the experiment as a random effect, linear mixed model analysis was used in a 2-step approach, whereby variables with a P < 0.30 in univariate analysis were included within the subsequent multivariate analysis. Variables with P < 0.05 in the multivariate analysis were retained in the final models. Model selection and evaluation were based on corrected Akaike information criteria, the root mean square prediction errors, and concordance correlation coefficients. A higher frequency of FP was observed in flocks lacking enrichment (P < 0.001), with increased age (P = 0.001), and in cage housing systems (P = 0.002). Similarly, FD increased in flocks lacking enrichment (P = 0.018), with increased age (P < 0.001), in the absence of beak trimming (P = 0.001) and in cage housing systems (P = 0.042). This meta-analysis confirmed the effectiveness of environmental enrichment in reducing FP and FD. Nevertheless, the modest ability of enrichment to dampen FD (-0.14 ± 0.06, 1-4 scale) suggests that other management strategies must be implemented in conjunction with environmental enrichment to successfully manage FP and resulting FD.

Effects of nest boxes in natural mating colony cages on fear, stress, and feather damage for layer breeders1,2,3

Colony cages are commonly used in China for the natural mating of layer breeders. However, feather pecking (FP) is a major problem in this system, and feather damage mainly due to FP needs to be alleviated. The objective of this study was to investigate the effects of nest boxes provided in colony cages. Each colony cage confined 10 roosters and 90 laying hens. The use of nest boxes as it relates to age, feather damage, sexual behavior, fertility, and fearfulness was evaluated. Thyroid hormones, which are considered to be physiological indicators of various forms of stress in poultry and may be correlated with the quality of feather coverage, were also tested. The control group and the nest box group each had 12 replicates, totaling 24 identical cages. Analyses were conducted using the linear mixed models procedure of SPSS Statistics 22.0. The results showed that the control group had a significantly higher proportion of hens with feather damage to 4 specific body regions (back, rump, tail, and belly) compared to the nest box group (P < 0.05). Increasing the use of the nest boxes took place from weeks 41 to 47 and at 53 wk of age, as seen by the percentage of eggs and number of sitting events in the nests, number of hens using the nests, and frequency of visits. There were no significant differences in fertility, the occurrence of mounting, or full copulation behavior between the 2 groups. Hens in the control group showed a significantly longer duration of tonic immobility at 43, 49, and 55 wk of age (P < 0.05). No significant differences were found between groups for the concentration of triiodothyronine or thyroxine, but a significantly higher concentration of corticosterone was measured in the control group than in the nest box group (P < 0.05). In conclusion, hens with access to nest boxes during the laying period had a decreased FP frequency, fewer damaged feathers, lower plasma corticosterone secretion, and were less fearful. This information contributes to the understanding of the FP behavior and stress sensitivity of layer breeders, which will provide a basis for the development and optimization of the colony cage equipment.

Effects of different claw-shortening devices on claw condition, fear, stress, and feather coverage of layer breeders

Natural mating colony cage systems for parent-stock layer breeders have been widely adopted by many commercial farms in China. However, the environment is still relatively barren, so enrichment devices such as claw abrasives can be provided. Hens living in wire cages lack the opportunity to abrade their claws, resulting in uncontrolled claw growth. The objective of this study was to investigate the effects of claw abrasive devices (CADs). Three different CADs were investigated: abrasive strips (T1), metal plates with holes (T2) and rubber mats with grooves (T3); cages without CADs acted as controls (T4). Claw length and sharpness, foot health, feather coverage, fear and physiological stress and mortality of the layer breeders were evaluated. Twelve replicates were used for each treatment, a total of 48 identical cages. Results showed that CADs had significant effects on claw length and sharpness of both hens and roosters. Birds in the T1 group had the shortest claw length and bluntest claw sharpness at 22, 32, 42, and 52 wk of age (P < 0.05). T1, T2, and T3 had higher scores for claw condition and significantly better overall plumage condition on the back and rump than T4 (P < 0.05). Hens in the T4 group were more susceptible to the tonic immobility, novel object, and avoidance distance tests. No significant differences were found between groups in concentration of triiodothyronine, thyroxine or 5-HT, except a significantly higher concentration of corticosterone in T4 compared to T1, T2, and T3 (P < 0.05). Overall mortality and mortality from cannibalism were both significantly higher in T4 than in T1, T2, and T3 (P < 0.05). In conclusion, hens with access to CADs during the laying period had shorter and blunter claws, less damaged plumage, a lower plasma corticosterone secretion and mortality rate and were less fearful.

Feather pecking in laying hens housed in free-range or furnished-cage systems on French farms

1. Beak trimming is currently used in France to avoid the negative consequences of severe feather pecking (SFP). However, this practice is controversial in terms of animal welfare, and forbidden in some European countries.2. This study aimed to assess the prevalence of SFP in French laying hen farms, to describe how farmers manage this behavioural disorder and to better understand the risk factors involved.3. A study was carried out from April 2015 to June 2016. Visits were paid to 79 flocks kept in furnished cages (FC) and 80 flocks in a free-range (FR) system. All the hens had trimmed beaks and were genotypically brown. The information collected included feather cover, skin damage, beak condition, farm and poultry house characteristics, livestock performance and management.4. The prevalence of SFP in FC flocks was estimated at 32.9% (IC = 95%, [22.5; 43.3]) and the prevalence of cannibalism as 2.5% (IC = 95%, [0.7; 8.8]) at 70 weeks of age. The prevalence of SFP in FR flocks was estimated to be 23.8% (IC = 95%, [14.5; 31.1]) and the prevalence of cannibalism was 8.8% (IC = 95%, [4.3; 17.0]) at 61 weeks of age.5. In FC flocks, SFP was associated with the combination of genotype, type and length of perches, cage area per hen, type of lighting, number of hens per cage and farm location. In FR flocks, feather cover was associated with use of the outdoor run, lighting programme, genotype, farm location and date of house construction.

Feather Pecking and Cannibalism in Non-Beak-Trimmed Laying Hen Flocks-Farmers' Perspectives

Pecking-related problems are common in intensive egg production, compromising hen welfare, causing farmers economic losses and negatively affecting sustainability. These problems are often controlled by beak trimming, which in Finland is prohibited. An online questionnaire aimed to collect information from farmers about pecking-related problems in Finnish laying hen flocks, important risk factors and the best experiences to prevent the problems. Additionally, the farmers' attitudes towards beak trimming were examined. We received 35 responses, which represents about 13% of all Finnish laying hen farms with ≥300 laying hens. The majority of respondents stated that a maximum of 5⁻7% incidence of feather pecking or 1⁻2% incidence of cannibalism would be tolerable. The majority of respondents (74%) expressed that they would definitely not use beak-trimmed hens. Only two respondents indicated that they would probably use beak-trimmed hens were the practice permitted. Among risk factors, light intensity earned the highest mean (6.3), on a scale from 1 (not important) to 7 (extremely important). Other important problems included those that occurred during rearing, feeding, flock management and problems with drinking water equipment (mean 5.9, each). The most important intervention measures included optimal lighting and feeding, flock management, and removing the pecker and victim. Concluding, Finnish farmers had strong negative attitudes towards beak trimming. The study underlines the importance of flock management, especially lighting and feeding, in preventing pecking problems and indicates that it is possible to incorporate a non-beak-trimming policy into sustainable egg production.

On-Farm Evaluation of an Automatic Enrichment Device with Maize Silage for Laying Hens

Challenges in alternative housing for laying hens are barren functional areas such as winter gardens and the occurrence of behavioral disorders. Environmental enrichment is a measure to deal with these problems. Therefore, an enrichment device offering maize silage automatically was tested in two winter gardens on-farm. The use of the winter gardens and the times individual hens stayed there and occupied themselves with the maize silage were determined in a temporary preference test. The proportion of residing hens was significantly larger in the enriched winter garden. The mean time individual hens stayed in the enriched winter garden ranged from 02:16 ± 02:22 (mm:ss) to 03:17 ± 02:27, whereas the time ranged from 00:18 ± 00:32 to 00:59 ± 01:19 in the other winter garden (p < .05). Once the enrichment device ran in both winter gardens, no differences were found between the observed parameters. On average, the hens occupied themselves with the enrichment material for 03:50 ± 02:12 to 05:01 ± 03:06. Thus, based on its use and acceptance by the laying hens, the automatic device provided adequate environmental enrichment.

Effect of simple and low-cost enrichment items on behavioral, clinical, and productive variables of caged laying hens

Housing layers in battery cages is a practice still used by many countries but it has been criticized because of its influence on behavioral repertoire of birds. We investigated whether simple and affordable enrichment devices alone impact behavior, foot condition and performance of laying hens housed in conventional cages. Hens were divided into plain cages (CON), cages with perches (PER), and cages with tassels and scratch-pads (ENR), and parameters were evaluated before and after enrichment placement. After perch placement inactivity, drinking and competition for space reduced 35.6%, 40.8% and 70.3%, respectively, whereas social interaction increased 19.3%. Both modifications decreased locomotion (75.0% and 42.4% for PER and ENR respectively) and abnormal behaviors (62.5% and 43.9.4% for PER and ENR respectively). None of the performance variables were affected by ENR or PER. Thermography was more efficient than visual inspection in detecting subclinical bumblefoot, and it confirmed that PER reduced subclinical and clinical cases. Our findings indicate that perches increased welfare-related behaviors and foot health of hens, supporting the use of these inexpensive and highly adaptable alternatives for the enrichment of battery cages.

Environmental Enrichment for Broiler Breeders: An Undeveloped Field

Welfare problems, such as hunger, frustration, aggression, and abnormal sexual behavior, are commonly found in broiler breeder production. To prevent or reduce these welfare problems, it has been suggested to provide stimulating enriched environments. We review the effect of the different types of environmental enrichment for broiler breeders, which have been described in the scientific literature, on behavior and welfare. Environmental enrichment is defined as an improvement of the environment of captive animals, which increases the behavioral opportunities of the animal and leads to improvements in biological function. This definition has been broadened to include practical and economic aspects as any enrichment strategy that adversely affects the health of animals (e.g., environmental hygiene), or that has too many economic or practical constraints will never be implemented on commercial farms and thus never benefit animals. Environmental enrichment for broiler breeders often has the purpose of satisfying the behavioral motivations for feeding and foraging, resting, and/or encouraging normal sexual behavior. Potentially successful enrichments for broiler breeders are elevated resting places, cover panels, and substrate (for broiler breeders housed in cage systems). However, most of the ideas for environmental enrichment for broiler breeders need to be further developed and studied with respect to the use, the effect on behavior and welfare, and the interaction with genotype and production system. In addition, information on practical use and the economics of the production system is often lacking although it is important for application in practice.

Providing laying hens in group-housed enriched cages with access to barley silage reduces aggressive and feather-pecking behaviour

Two trials were conducted to study the effect of feeding barley silage on the behaviour and performance of beak-trimmed laying hens. In each trial, 20 hens and 2 roosters were housed in each of eight group-housed enriched cages, with four cages provided a laying hen diet and four cages additionally given free access to barley silage. Egg production and quality, and hen behaviour were assessed throughout the trials (Trial One 20–30 weeks; Trial Two 19–28 weeks). Data were analysed using Proc Mixed of SAS 9.4 and differences were significant when P ≤ 0.05. Silage-fed hens consumed 41 (13.9 g DM) and 50 (13.5 g DM) grams of silage per hen per day in Trials One and Two, respectively, while consuming less layer diet. Birds fed silage spent less time expressing aggressive and feather-pecking behaviours and in nest boxes, and more time feeding than control birds. Egg production, egg quality, and bird weight were not affected by treatment; yolk colour was darker for the silage treatment. Feathering quality was improved in silage-fed birds compared to control birds. It was concluded that providing hens with access to barley silage can improve welfare indicators without negatively affecting the egg production and egg quality.

Individual Consistency of Feather Pecking Behavior in Laying Hens: Once a Feather Pecker Always a Feather Pecker?

The pecking behavior [severe feather, gentle feather, and aggressive pecks (AP)] of individual White Shaver non-cage laying hens (n = 300) was examined at 21, 24, 27, 32, and 37 weeks. Hens were housed in 30 groups of 10 hens each and on 3 cm litter with access to a feeder, perch, and two nest boxes. The number of severe feather pecks given (SFPG) and received (SFPR) was used to categorize hens as feather peckers (P), victims (V), neutrals (N), or feather pecker-victims (PV) at each age. Hens categorized as PV exhibited pecking behaviors similar to P and received pecks similar to V. SFP given were correlated with APs given, but not with gentle feather pecks (GFP) given throughout the study. State-transition plot maps illustrated that 22.5% of P remained P, while 44% of PV remained PV throughout the duration of the study. Lifetime behavioral categories identified hens as a consistent feather pecker (5%), consistent neutral (3.9%), consistent victim (7.9%), consistent feather pecker-victim (29.4%), or inconsistent (53.8%) in their behavioral patterns throughout their life. Consistent feather peckers performed more SFP than hens of other categories, and consistent neutral hens received fewer GFP than consistent feather PV. No differences in corticosterone or whole blood serotonin levels were observed among the categories. Approximately, half of the population was classified as a feather pecker at least once during the study, while the remainder was never categorized as a feather pecker. Therefore, even if the development and cause of feather pecking may be multifactorial, once the behavior has been developed, some hens may persist in feather pecking. However, as some hens were observed to never receive or perform SFP, emphasis should be made to select for these hens in future breeding practices.