Keel bone fractures affect the majority of laying hens in commercial egg production and represent one of the most significant and underappreciated welfare problems in modern agriculture.
Keel bone fractures cause chronic pain that hens experience throughout the laying period, often for months. The difficulty of detecting fractures without physical examination means most affected hens receive no pain management. Hens instinctively mask signs of weakness as a predator-avoidance behaviour, making the problem nearly invisible to casual observation. The transition away from battery cages, while positive for many welfare outcomes, has not resolved keel bone fractures and may have increased them in poorly designed aviary systems. Solving this problem requires a combination of genetic selection, housing design improvements, and routine welfare monitoring.