Keel bone fractures affect a substantial proportion of laying hens in cage-free and aviary systems and represent a significant welfare concern requiring design and management solutions.
Keel bone fractures represent a serious welfare problem that has unexpectedly accompanied the transition from cages to cage-free and aviary systems. The paradox is that systems intended to improve welfare have introduced a new significant welfare harm. Hens with fractured keel bones experience chronic pain that reduces their ability to compete for resources and may cause them to avoid perches that would otherwise improve their welfare. The solutions are multifactorial: genetic selection for stronger bones, aviary design that reduces collision risk, lower perch angles, and resilient perch surfaces all show promise in reducing fracture rates. Welfare certification schemes increasingly require keel bone assessment as part of auditing, accelerating industry adoption of preventive measures.