Laying hens suffer from severe osteoporosis due to calcium demands of egg production — a largely invisible welfare problem that causes bone fractures during housing and at slaughter.
Laying hen bone disease is an underrecognized welfare crisis. The calcium demands of intensive egg production strip structural calcium from bones at rates that exceed dietary replenishment, causing a form of osteoporosis that leaves bones so fragile they break from normal activities. Keel bone fractures — a specific and measurable welfare indicator — affect the majority of commercial laying hens regardless of housing system. Fractured keels cause pain indicated by behavioral changes. At slaughter, post-mortem examination reveals the scale of bone fracture in commercial flocks. The problem is partially manageable through optimized dietary calcium forms, perch design in cage-free systems, and breeding selections that better balance egg production with bone health — but fundamental genetic reform is required for lasting solutions.