Examining the relationship between different naturally-occurring maxillary beak shapes and their ability to cause damage in commercial laying hens

1. Using chicken models to avoid unnecessary harm, this study examined the relationship between naturally-occurring maxillary (top) beak shapes and their ability to cause pecking damage.2. A selection of 24 Lohmann Brown laying hens from a total population of 100 were sorted into two groups based on their maxillary beak shape, where 12 were classified as having sharp beaks (SB) and 12 as having blunt beaks (BB).3. All hens were recorded six times in a test pen which contained a chicken model (foam block covered with feathered chicken skin) and a video camera. During each test session, the number of feathers removed from the model, the change in skin and block weight (proxies for tissue damage) and the percentage of successful pecks (resulting in feather and/or tissue removal) were recorded.4. SB hens removed more feathers from the model and had a greater change in skin weight than BB hens. The mean number of pecks made at the model did not differ between the beak shape groups; however, SB hens had a greater percentage of successful pecks, resulting in feather and/or tissue removal, compared to BB hens.5. In conclusion, SB hens were more capable of removing feathers and causing damage. Birds performed more successful pecks resulting in feather and/or tissue removal as they gained experience pecking at the model.</p

A Literature Review of Broiler Chicken Welfare, Husbandry, and Assessment

Literature surrounding key aspects of broiler chicken husbandry and its relation to animal welfare are reviewed, for the context of broiler chicken farming in Indonesia. This review focuses on husbandry of commercially grown broiler chickens on farm, including light systems, litter substrates, lameness, contact dermatitis, heat stress and climate control. Common assessment methods of broiler chicken welfare are also reviewed. Key broiler welfare issues in Indonesia are likely to be heat stress, lameness, and contact dermatitis, and these may result in reduced productivity. Considering photoperiod and reviewing litter substrate management could be economical and practical ways to improve welfare. Foot pad dermatitis and lameness are useful indicators of broiler welfare, and the high market demand for chicken feet in Asia could serve as an incentive to improve broiler welfare and chicken foot quality in the region

Keel bone fractures induce a depressive-like state in laying hens

In commercial flocks of laying hens, keel bone fractures (KBFs) are prevalent and associated with behavioural indicators of pain. However, whether their impact is severe enough to induce a depressive-like state of chronic stress is unknown. As chronic stress downregulates adult hippocampal neurogenesis (AHN) in mammals and birds, we employ this measure as a neural biomarker of subjective welfare state. Radiographs obtained longitudinally from Lohmann Brown laying hens housed in a commercial multi-tier aviary were used to score the severity of naturally-occurring KBFs between the ages of 21–62 weeks. Individual birds’ transitions between aviary zones were also recorded. Focal hens with severe KBFs at 3–4 weeks prior to sampling (n = 15) had lower densities of immature doublecortin-positive (DCX+) multipolar and bipolar neurons in the hippocampal formation than focal hens with minimal fractures (n = 9). KBF severity scores at this time also negatively predicted DCX+ cell numbers on an individual level, while hens that acquired fractures earlier in their lives had fewer DCX+ neurons in the caudal hippocampal formation. Activity levels 3–4 weeks prior to sampling were not associated with AHN. KBFs thus lead to a negative affective state lasting at least 3–4 weeks, and management steps to reduce their occurrence are likely to have significant welfare benefits

Poor body condition is associated with lower hippocampal plasticity and higher gut methanogen abundance in adult laying hens from two housing systems

It is still unclear which commercial housing system provides the best quality of life for laying hens. In addition, there are large individual differences in stress levels within a system. Hippocampal neurogenesis or plasticity may provide an integrated biomarker of the stressors experienced by an individual. We selected 12 adult hens each with good and poor body condition (based on body size, degree of feather cover and redness of the comb) from a multi-tier free range system containing H&N strain hens, and from an enriched cage system containing Hy-Line hens (n = 48 total). Immature neurons expressing doublecortin (DCX) were quantified in the hippocampus, contents of the caecal microbiome were sequenced, and expression of inflammatory cytokines was measured in the spleen. DCX(+) cell densities did not differ between the housing systems. In both systems, poor condition hens had lower DCX(+) cell densities, exhibited elevated splenic expression of interleukin-6 (IL6) mRNA, and had a higher relative caecal abundance of methanogenic archea Methanomethylophilaceae. The findings suggest poor body condition is an indicator that individual hens have experienced a comparatively greater degree of cumulative chronic stress, and that a survey of the proportion of hens with poor body conditions might be one way to evaluate the impact of housing systems on hen welfare