This study presents an overview of the current welfare status of laying hens in Sweden and is based on records from 397 flocks housed in 193 farms. It was a collaboration between researchers at the Department of Animal Environment and Health at SLU and the Swedish Egg Association and used a novel analytical approach, called additive Bayesian networks, to investigate the inter-relationships between housing system, management and animal welfare indicators.
Overall mortality was low (<0.6%), severe mite infestations rare (4% of flocks). Feather condition was satisfactory in 79% of flocks and when plumage damage was unsatisfactory, it was directly associated only with the age of the flock, not with any management or housing variables. The results suggest that problems with cannibalism and feather pecking in Swedish flocks have reduced considerably since the ban of battery cages in 1988. Results show that lighting and air quality were an issue in 5% and 8% of flocks, respectively. The complex inter-relationship with several management and housing variable, however, implies that there are several options for intervention to reduce these problems.
Comin, A., Jeremiasson, A., Kratzer, G., Keeling, L.J. 2019. Revealing the structure of the associations between housing system, facilities, management and welfare of commercial laying hens using Additive Bayesian Networks. Preventive veterinary medicine 164: 23-32.