PhD defence

What affects nesting behaviour in broiler breeders? The role of motivation, physical ability and social opportunity

Summary:

Broiler breeders are expected to lay eggs like laying hens, but have been selected for fast growth of their offspring. This selection has affected their physiology, but their behaviour also seems influenced. Broiler breeders lay relatively more eggs outside of the nests (so-called floor eggs), which is a sign of decreased welfare as well as an economic cost for the farmer. We found that offering wooden nests rather than plastic nests increases the motivation of the hen to lay her egg in the nest. Although foot pad dermatitis became increasingly severe with age, this did not seem to limit the ability of the hen to reach the nest. We observed that some genetic lines of broiler breeders perform excessive gregarious nesting, which limits the opportunity to visit the nest and thus increases percentage of floor eggs. Broiler breeders males affect the spatial behaviour of hens, but their exact role in nesting behaviour remains unclear.