Outdoor pig production systems provide environmental enrichment inherently unavailable in indoor systems, but welfare outcomes depend on management quality and supplementary provision.
Outdoor pig welfare provides natural behavior opportunities that are the most significant welfare advantage of the production system. Rooting in soil, wallowing, grazing, and ranging across larger areas than indoor systems allow genuine expression of species-typical behaviors that indoor systems, even enriched ones, cannot replicate. The welfare of outdoor systems is not automatic - poor pasture management creates welfare problems from excessive mud and limited foraging opportunity, and supplementary nutrition must address deficiencies. The behavioral evidence for outdoor pig welfare superiority is strong for core natural behaviors, while health welfare can be comparable between well-managed indoor and outdoor systems.