Pig Aggression and Regrouping Management

Mixing unfamiliar pigs triggers aggression that causes injury and chronic stress. Evidence-based management significantly reduces harm during inevitable regrouping events.

Key Facts

Pig hierarchies are established through fighting that can cause serious injuries including bite wounds
Mixing at different production stages including weaning, transfer, and marketing is unavoidable in most systems
Low-light introduction periods reduce the intensity of initial fighting at regrouping
Providing multiple escape routes and visual barriers reduces intensity and duration of aggression
Genetic selection for reduced aggression is a long-term solution being explored in breeding programs

Welfare Considerations

Regrouping aggression is one of the most significant and frequent welfare events in commercial pig production. Each mixing event subjects pigs to stress and potential injury as new hierarchies form. While some aggression is unavoidable in a hierarchical social species, management strategies that reduce its intensity and duration meaningfully reduce welfare harm.

What You Can Do

Support pig farming systems that minimize regrouping frequency through stable group management
Choose pork from certified higher welfare systems with documented aggression management protocols
Advocate for farmer training in evidence-based pig mixing management
Support research into genetic and management approaches to reducing pig aggression