Keel bone fractures affect the majority of laying hens in many commercial systems and represent one of the most significant unaddressed welfare issues in modern poultry production.
Keel bone fractures represent a welfare crisis affecting billions of hens annually yet receiving relatively little public attention compared to housing system debates. The irony is that welfare improvements in housing, particularly the shift from battery cages to aviaries, have not resolved and in some cases have worsened keel fracture prevalence due to collision with structures during flight. The fractures cause pain that hens attempt to conceal, consistent with prey animal behaviour, but analgesic studies confirm significant pain experience. Breeding for bone density, housing design to reduce collision risk, and management practices reducing fearful flight responses all have potential to reduce prevalence. No single intervention is sufficient; a multi-factorial approach addressing genetics, design, and management is required.