Keel bone fractures affect the majority of laying hens in many commercial systems and cause chronic pain that significantly impairs welfare. Understanding this largely invisible problem is essential for driving meaningful reform.
Keel bone fractures represent one of the most numerically significant welfare problems in laying hen production. The fact that the majority of hens in many commercial systems — including those marketed as "higher welfare" — have experienced painful bone fractures indicates a welfare failure that is largely invisible to consumers and insufficiently addressed by current standards. Unlike conditions with obvious external signs (feather loss, injuries), keel bone damage requires palpation or radiography to detect and does not produce dramatic visible welfare signals. Pain from keel bone fractures meets the threshold for clinical significance in peer-reviewed welfare science, yet regulatory and certification responses have been slow. The finding that aviary systems — intended as welfare improvements over enriched cages — have higher fracture prevalence than some cage systems illustrates the complexity of welfare trade-offs and the importance of addressing specific welfare outcomes rather than assuming system type determines welfare level.