Keel bone fractures affect 50-80% of laying hens in commercial flocks, causing chronic pain and significantly reducing welfare. This largely invisible welfare problem affects billions of hens globally.
Keel bone fractures represent one of the most significant and least publicly understood welfare problems in egg production. The scale is staggering — the majority of laying hens in commercial flocks in Europe and North America have fractured keels — but the problem is invisible to consumers and rarely communicated by industry. Hens with fractures show behavioral evidence of chronic pain: reluctance to use perches, altered posture, reduced movement, and modified vocalizations. The pain is not acute and dramatic but chronic and persistent, affecting welfare across weeks and months of the laying cycle. The causes are partly systemic — commercial laying breeds have been selected for egg production rates that deplete calcium from bones — and partly environmental: perch design, aviary geometry, and housing density all influence fracture risk. Solutions exist across multiple levels: breed selection for stronger bones, perch design that reduces collision landing forces, early-life calcium supplementation, and housing design that reduces high-risk flight paths. Progress is being made but slowly relative to the scale of suffering.