The majority of laying hens in cage-free systems suffer keel bone fractures. This painful and prevalent condition is a priority welfare problem in commercial egg production.
Keel bone fractures represent a major and largely unacknowledged welfare crisis in commercial egg production, including systems marketed as higher-welfare. The keel bone — the breastbone — is frequently fractured as hens navigate multi-tier cage-free systems, falling from perches or colliding with structures. These fractures cause chronic pain that reduces activity, feeding, and social interaction. The problem is linked to selective breeding that prioritizes egg production over bone strength. Solutions include improved system design, breeding selection for bone quality, and gentle lighting transitions in aviary systems.