Dr. Ian J. H. Duncan, Professor Emeritus and Emeritus Chair in Animal Welfare, University of Guelph
The welfare pros for traditional cages include a reduction in the incidence of infectious diseases transmitted through the gut, a reduction in mortality rates, and a lower incidence of feather pecking and cannibalism compared to floor systems. In addition, caging systems generally have lower group sizes resulting in less social friction. However, the welfare cons of traditional cages outweigh the pros and include frustration of nesting behaviour, lack of forging and dust-bathing opportunities, lack of physical space to adopt some normal postures and lack of social space to keep preferred distance from other hens. It is also difficult and very time consuming to inspect hens in battery cages and this is often not done frequently enough. Well-designed furnished cages overcome some, but not all, of these welfare problems. It would seem that, in Canada, the best welfare-friendly husbandry system for egg production will be some variety of aviary.
1. By separating birds from their feces, caging systems give laying hens some protection from infections passed through the gut as well as reducing social friction by keeping hens in fairly small groups
2. Traditional battery cages severely frustrate hens before they lay an egg (7 days out of 8) by not providing a suitable nesting site
3. All cage systems frustrate hens by not providing sufficient opportunities for foraging or the amount of space that the hens themselves would prefer.
Ian Duncan is Professor Emeritus and Emeritus Chair in Animal Welfare at the University of Guelph. He has been carrying our research into animal welfare since 1965 and was thus one of the first people to bring a scientific approach to solving welfare problems. He has developed methods of “asking” animals what they feel about the conditions in which they are kept and the procedures to which they are subjected.