Laying hens suffer from epidemic rates of osteoporosis due to the extreme calcium demands of egg production, causing painful fractures that represent a major but underrecognized welfare problem.
Laying hen osteoporosis represents one of the most widespread and least visible welfare problems in animal agriculture. The calcium demands of producing an eggshell every 24-26 hours draw on structural bone when dietary calcium is insufficient, progressively weakening the skeleton over the laying cycle. Keel bone fractures - affecting a majority of commercial hens - cause chronic pain that impairs natural behavior including perching, dustbathing, and movement. Unlike obvious external injuries, keel bone fractures require palpation or radiography to detect, making their prevalence invisible in routine welfare assessment. The condition is partly genetic and partly environmental, creating opportunities for improvement through breeding programs, housing design, and nutritional management.