Group housing for pigs represents a significant welfare improvement over individual stalls, but requires careful management to ensure social harmony and prevent aggression injuries.
Group housing is a meaningful welfare advance for pigs, allowing movement, social interaction, and the expression of foraging and exploratory behaviors impossible in individual stalls. However, the transition from sow stalls to group housing brought a new challenge: aggression when unfamiliar pigs are mixed. Establishment fights involve biting, chasing, and sustained conflict that causes injuries, stress, and sometimes death. Good management — stable group composition from an early age, adequate space, and appropriate enrichment — dramatically reduces aggressive outbreaks. The welfare improvement from group housing is real and substantial, but requires ongoing management commitment to deliver its benefits.