Providing pigs with outdoor access or deep-litter systems that allow rooting and exploration produces consistent welfare improvements across behavioral, physiological, and health measures.
The behavioral and physiological evidence for the welfare benefits of outdoor access for pigs is extensive and consistent. Pigs raised outdoors show lower aggression, more positive social interactions, greater behavioral diversity, and measurably lower chronic stress indicators than indoor pigs in barren environments. The ability to root, wallow, and explore addresses the most fundamental behavioral needs of an animal that evolved as a forest and grassland forager. Consumer willingness to pay for outdoor-reared pork is the primary economic driver of outdoor system adoption. Certification schemes that require genuine outdoor or enriched indoor access provide market channels that reward producers for welfare investment and give consumers a meaningful choice.