Pigs are highly social animals that form complex relationships within stable groups. Group housing systems that respect their social needs represent a significant welfare improvement over individual confinement.
Pig social welfare has been a driver of significant regulatory change in Europe and is increasingly influencing producer practice globally. Pigs in stable social groups engage in affiliative behaviors — nosing, grooming, play — that are indicators of positive emotional states and that cannot occur in individual confinement. Gestation crates that prevent any social interaction or movement represent the most extreme example of social deprivation in commercial animal agriculture. EU and UK regulations requiring group housing after early gestation represent a major welfare improvement, though enforcement quality varies across member states. Group housing introduces management challenges including establishing stable hierarchies (mixing unfamiliar pigs causes intense fighting), resource distribution to prevent dominant pig monopolization, and space requirements for subordinate animals to escape aggressive interactions. Stable groups formed early in production and maintained throughout — rather than repeatedly mixed — represent the welfare optimum for commercially managed pigs.