Keel bone fractures affect 50-80% of laying hens in commercial systems and cause chronic pain. This is the most prevalent welfare problem in layer production worldwide and is largely invisible to consumers.
Keel bone fractures represent the most prevalent form of chronic pain in food animal production globally, yet they receive far less public and policy attention than gestation crates or battery cages. The invisibility of this welfare crisis reflects how easily animal suffering is missed when it is internal, gradual, and affects animals in systems that are already considered relatively high welfare by industry standards. Cage-free and free-range systems were adopted partly for welfare reasons, yet keel bone fracture prevalence is actually higher in these systems than in conventional cages because hens have more opportunity to collide with perches and fall from heights. This demonstrates that welfare cannot be assumed from housing type alone; it must be measured through outcome-based indicators.