Outdoor access systems for pigs provide significant welfare benefits but require careful management to prevent welfare problems from exposure and disease.
Outdoor access for pigs transforms welfare by enabling fundamental behaviors denied in indoor systems: rooting in actual soil, wallowing in mud to thermoregulate, foraging for varied foods, and exploring environmental novelty. These behaviors satisfy intrinsic motivational systems that barren indoor environments frustrate chronically. The welfare benefits require management attention to weather protection, parasitic disease control, and stocking density on outdoor areas to prevent erosion and mud that eliminates the behavioral benefits. Well-managed outdoor systems represent some of the highest welfare pig production available commercially.