Keel bone fractures are a well-known welfare problem in modern commercial laying hen systems. The present study sought to identify genetic variation in relation to keel bone fracture susceptibility of 4 distinct crossbred and one pure line, and by extension, possible breeding traits. Susceptibility to fractures were assessed using an ex vivo impact testing protocol in combination with a study design that minimized environmental variation to focus on genetic differences. The 5 crossbred/pure lines differed in their susceptibility to keel bone fractures with the greatest likelihood of fracture in one of the 3 commercial lines and the lowest susceptibility to fractures in one of the experimental lines. Egg production at the hen-level did not differ between the crossbred/pure lines (P > 0.05), though an increased susceptibility to keel bone fractures was associated with thinner eggshells and reduced egg breaking strength, a pattern consistent among all tested crossbred/pure lines. Our findings suggest an association between egg quality and bone strength which appeared to be independent of crossbred/pure line. The findings indicate the benefit of the impact methodology to identify potential breeding characteristics to reduce incidence of keel fracture as well as the potential relationship with eggshell quality.

Despite societal concerns about the welfare of commercial laying hens, little attention has been paid to the welfare implications of the choices made by the genetics companies involved with their breeding. These choices regarding trait selection and other aspects of breeding significantly affect living conditions for the more than 7 billion laying hens in the world. However, these companies must consider a number of different commercial and societal interests, beyond animal welfare concerns. In this article we map some of the relevant dilemmas faced by genetics companies in order to outline the scope of opportunities to improve welfare under current market conditions. This includes identifying cases where different animal welfare concerns conflict. We discuss the moral responsibility of laying hen genetics companies and the welfare implications that derive from the choices they make and the policies they follow. In addition to evaluating a selection of predominant current practices and breeding goals, we outline different angles from where to assess the moral legitimacy of various industry practices and policies. We discuss specific issues such as injurious pecking, bone health, induced moulting, chick culling and the circumstances of breeding stock.