Access to nest boxes for egg-laying is a fundamental behavioral need for laying hens, strongly motivated and associated with significant distress when denied. Nest box provision is a key welfare requirement in non-cage systems.
Nest-seeking behavior in laying hens before egg-laying is one of the most highly motivated behaviors in the species. Research showing that hens work hard to access nests (pressing weighted doors, crossing unpleasant substrates) even when floor laying is available demonstrates the strength of this motivation. Denying nest access causes acute distress that is physiologically measurable and behaviorally obvious. The welfare case for providing adequate nest boxes is therefore among the strongest in laying hen welfare science, and has directly influenced legislation requiring nest provision in enriched colony cages as minimum EU standards. The quality and placement of nests matters as much as their number - welfare-positive nest provision gives all hens equal access to appropriate nesting locations.