Osteoporosis and bone fractures are among the most serious and widespread welfare problems in commercial laying hens. Understanding this issue is essential to improving egg production welfare standards.
Bone health represents one of the most significant and least publicly recognized welfare crises in commercial egg production. The combination of intensive egg-laying genetics and housing systems that restrict physical activity has produced a population of birds chronically compromised by osteoporosis and fracture. Keel bone fractures — in the prominent breastbone — cause chronic pain that is difficult to assess but detectable through behavioral indicators including reduced activity, abnormal posture, and wing droop. The fractures typically result from impacts with perches, equipment, or other birds. Cage-free and aviary systems that provide flight opportunity and perching exercise show improved bone density but not necessarily reduced fracture rates due to increased movement and impact risks. Selective breeding for improved bone strength represents the most promising long-term solution. Until breeding changes are implemented, welfare monitoring that includes fracture prevalence at slaughter provides essential data for system improvement.