Nesting motivation in laying hens is one of the most intensely studied welfare-relevant behaviours, with deprivation causing measurable distress that cage systems fail to address.
Nesting motivation in laying hens is one of the most compelling demonstrations of the welfare costs of cage confinement. A hen without access to an appropriate nest box before laying shows progressive behavioural agitation — pacing, increased vocalisation, and repeated fruitless searching — that constitutes clear distress. The motivation is so strong that hens will work harder for nest box access than for food. Enriched colony cages provide a nominal nest area, but competition for limited shared nest space means many hens lay eggs on the cage floor in the absence of privacy. Adequate nest box provision — one per five hens as a minimum — with appropriate seclusion is a welfare requirement that free-range and aviary systems can meet and cage systems cannot.