Keel bone fractures affect the majority of laying hens in most production systems and cause chronic pain - this is now recognised as the most prevalent welfare crisis in the egg industry.
Keel bone fracture welfare represents a paradox in egg production welfare. Systems intended to improve welfare - enriched cages and free-range - have higher fracture rates than battery cages because hens are more active and collisions with structures are more frequent. The welfare solution requires both system design improvement and genetic change - perch positioning and material can reduce collision risk while breeding for stronger keel bones addresses root cause. The scale of the problem - affecting the majority of all laying hens - makes this one of the highest-priority welfare issues in animal agriculture. Consumer pressure for welfare solutions creates market incentive for producers to invest in research and system improvement.