Extreme crowding in laying hens during a recurrent smothering outbreak.

BACKGROUND: Piling, a behaviour where hens crowd together, is referred to as smothering if mortalities result. Smothering is a considerable concern for the egg industry, yet is vastly understudied. METHODS: During an outbreak of recurrent smothering, continuous video footage captured a commercial, free-range flock over 35 days. We describe the piling behaviour observed and potential associations with productivity and flock health indicators. RESULTS: Forty-eight piles were filmed, with a maximum density of 187.93 birds/m2 and up to 1204 birds in one pile. Piling occurred in the same house location on 33 of 34 observation days, the first evidence of regularity in piling behaviour. Despite extreme bird densities, we did not find associations between piling extremity and productivity but did find associations with water:feed ratio and temperature range. CONCLUSION: This study describes the most extreme level of piling reported in literature and offers new insights into this problem behaviour and its consequences.

Slow-growing broilers are healthier and express more behavioural indicators of positive welfare.

Broiler chicken welfare is under increasing scrutiny due to welfare concerns regarding growth rate and stocking density. This farm-based study explored broiler welfare in four conditions representing commercial systems varying in breed and planned maximum stocking density: (1) Breed A, 30 kg/m2; (2) Breed B, 30 kg/m2; (3) Breed B, 34 kg/m2; (4) Breed C, 34 kg/m2. Breeds A and B were 'slow-growing' breeds (< 50 g/day), and Breed C was a widely used 'fast-growing' breed. Indicators of negative welfare, behavioural indicators of positive welfare and environmental outcomes were assessed. Clear differences between conditions were detected. Birds in Condition 4 experienced the poorest health (highest mortality and post-mortem inspection rejections, poorest walking ability, most hock burn and pododermatitis) and litter quality. These birds also displayed lower levels of behaviours indicative of positive welfare (enrichment bale occupation, qualitative 'happy/active' scores, play, ground-scratching) than birds in Conditions 1-3. These findings provide farm-based evidence that significant welfare improvement can be achieved by utilising slow-growing breeds. There are suggested welfare benefits of a slightly lower planned maximum stocking density for Breed B and further health benefits of the slowest-growing breed, although these interventions do not offer the same magnitude of welfare improvement as moving away from fast-growing broilers.