ARS | Publication request: Hen Welfare in Different Housing Systems

Submitted to: Journal of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: March 13, 2010
Publication Date: July 11, 2010
Citation: Lay Jr, D.C., Fulton, R.M., Hester, P.Y., Karcher, D.M., Kjaer, J., Mench, J.A., Mullens, B.A., Newberry, R.C., Nicol, C.J., O'Sullivan, N.P., Porter, R.E. 2010. Hen Welfare in Different Housing Systems [abstract]. Journal of Animal Science. 88:1027(E-Suppl. 2).

Technical Abstract: Recently, the public has begun to question the conditions under which intensively-managed livestock are housed. As a consequence of this concern, animal production practices, including egg production systems, have become subject to heightened levels of scrutiny. Animal welfare issues lie at the heart of the matter. However, improving animal welfare is no simple task. Multiple factors such as disease, skeletal and foot health, nutrition, pest and parasite load, behavior, stress, affective states and genetics influence the level of welfare that laying hens experience. Although the need to evaluate the influence that these factors exert under different housing systems is recognized, research into these areas is still in the early stages. However some facts are clear. Environments in which hens are exposed to litter and earth, provide a greater opportunity for disease and parasites. The more complex the environment, the more difficult it is to clean, and the larger the group size, the more easily disease and parasites are able to spread. Future development of appropriate vaccines will help combat this problem. Environments which limit movement can lead to osteoporosis, but environments which have increased complexity may expose hens to an increased incidence of bone fractures. The provision of a greater amount of space allows hens to perform a greater repertoire of behaviors, although some deleterious behaviors such as cannibalism and crowding, which results in smothering, can occur. Less is understood about the stress which each system imposes on the hen, but it appears that each system has its unique challenges relative to the stress response of the hen. Selective breeding for desired traits may help to improve the welfare of laying hens. Current experimental research indicates that certain traits such as feather pecking, cannibalism and bone strength may have a large genetic component. As a result, it may be possible to select for, and develop lines of, hens less likely to express such behaviors. It appears that no single housing system is ideal from a welfare perspective. Although environmental complexity increases behavioral opportunities, it also introduces difficulties in terms of disease and pest control. In addition, environmental complexity can create opportunities for the hens to express behaviors that are actually detrimental to their welfare. As a result, any attempt to evaluate the sustainability of a switch to an alternative housing system requires careful consideration of the merits and shortcomings of each housing system.