Keel bone fractures affect a majority of laying hens in many production systems and represent one of the most widespread and under-addressed welfare problems in egg production.
Keel bone fractures represent a significant and poorly publicised welfare problem that complicates the straightforward welfare comparison between cage-free and cage egg production. Hens in cage-free systems have better welfare in multiple dimensions but worse welfare in terms of keel bone health, because falls and collisions in complex multi-tier aviaries cause fractures that would not occur in cages. This does not justify returning to cages — the overall welfare balance of well-managed cage-free systems remains positive — but it does highlight the need for aviary design improvements, breed selection for bone strength, and pain management protocols for affected hens. Transparency about keel bone prevalence is essential for honest welfare communication.