Keel bone fractures affect the majority of laying hens in commercial systems, causing chronic pain that is one of the most pervasive welfare harms in modern egg production.
Keel bone fractures are now recognized as the most significant welfare issue in laying hen production globally. The keel bone runs along the hen's sternum, and fractures there cause ongoing pain with each breath and movement. Hens with fractured keels continue to lay eggs, masking their suffering from producers. Research indicates that appropriate perch design, ramp access, and substrate management can reduce fracture incidence. Genetic selection criteria that include bone health represent a longer-term solution requiring industry coordination.