Wean-to-finish systems raise pigs from weaning to market in a single building. Understanding welfare implications of this production model informs assessment of different system types.
Wean-to-finish systems have welfare advantages and challenges compared to multi-site production. The welfare benefit of eliminating building moves reduces transportation stress, social mixing stress, and the multiple new environment adaptations that multi-site systems impose. The welfare challenge is stocking density management: buildings stocked appropriately for market-weight pigs are overcrowded for small weaned pigs, but buildings stocked for weaned pigs will become overcrowded before market weight without aggressive sorting and removal. Social stability benefits are real but require management attention to ensure the stable hierarchy doesn't concentrate welfare harms on consistently subordinate individuals throughout the production cycle.