The natural social hierarchy in laying hens — the pecking order — has profound welfare implications, particularly when high stocking densities or inadequate resources create competition that escalates to injurious pecking.
High stocking density combined with inadequate resource provision is the primary driver of welfare-relevant pecking in laying flocks. When hens cannot avoid dominant individuals or access feed without confrontation, subordinates suffer chronic stress, nutritional deprivation, and physical injury. Beak trimming has historically been used to blunt the effects of injurious pecking, but it causes acute and potentially chronic pain and is increasingly restricted in legislation. The welfare solution lies upstream: adequate space, resource distribution, environmental enrichment, stable group composition, and breed selection for lower pecking propensity. Monitoring flock plumage and wound scores provides early warning of escalating aggression, allowing intervention before welfare deteriorates severely.