Pigs form lasting social bonds with familiar conspecifics. Disrupting these bonds through regrouping causes welfare suffering comparable to social loss in higher mammals. Managing social stability improves welfare.
Social bonds between pigs are real relationships that have welfare value. Disrupting these bonds through regrouping causes grief-like stress responses and social instability. Production systems designed to maintain stable social groups throughout the production cycle protect these bonds and the welfare benefits they provide. This is a welfare consideration that production system design decisions directly affect.