Keel bone fractures in laying hens are an under-recognized welfare crisis affecting the majority of commercial laying hens in all housing systems including cage-free.
Keel bone fractures are arguably the single most prevalent welfare problem in commercial laying hens globally. The condition is paradoxically worsened by cage-free systems — the perching and flight required in aviaries leads to more collisions and falls, increasing fracture risk compared to battery cages where hens cannot move enough to fracture keel bones. This creates a challenging situation for welfare advocates: cage-free systems improve many welfare dimensions (behavioral freedom, social complexity, access to scratch and dust) while simultaneously increasing keel bone fracture prevalence. Research is underway on perch design, aviary layout, litter management, and selective breeding approaches that could address fractures without compromising other welfare gains.