Nest box provision for laying hens is a fundamental welfare requirement, with design factors including substrate, darkness, and number significantly affecting nesting behavior and welfare outcomes.
Nest box welfare is defined by the strength of hens' pre-laying behavioral motivation - an internal state driving increasingly persistent behavior until a suitable nest site is found or the egg must be laid. Hens denied adequate nest access experience significant behavioral frustration during the pre-laying period, expressed through extended vocalizations, pacing, and ultimately floor-laying that represents failure of the system to meet a strong behavioral need. Well-designed nest provision that offers appropriate darkness, substrate, and adequate numbers removes a preventable welfare compromise from the daily life of every hen in the flock.