How keel bone fractures cause chronic pain in laying hens across all housing systems, and what research shows about solutions.
Keel bone fractures represent one of the most significant welfare challenges that persists across laying hen housing systems. The transition to cage-free housing — presented as a welfare improvement — has not reduced fracture rates as hoped; in some studies, fracture prevalence is higher in aviary systems than in enriched colonies. This does not argue for returning to cages but rather for recognizing that housing system alone is insufficient — genetic selection for bone strength, perch design optimization, and management practices that reduce collision frequency all contribute to the welfare solution. Research into this problem has intensified and shows genuine promise for meaningful reduction.