Outdoor access for pigs allows expression of rooting, wallowing, and ranging behaviour that indoor systems cannot adequately substitute.
Outdoor pig welfare is qualitatively different from indoor pig welfare in ways that metrics only partially capture. Rooting in real soil, wallowing in real mud, and ranging across real landscapes satisfies motivational systems that indoor enrichment — however sophisticated — approximates but cannot replicate. The welfare expression in outdoor systems is visible: pigs that have rooted, wallowed, and foraged are relaxed, socially positive, and behaviourally rich compared to the chronic low-level frustration of enrichment-deprived indoor pigs. The welfare cost of outdoor systems — exposure to predators, weather, and disease — is real but manageable with appropriate husbandry. For consumers seeking the highest welfare pork, outdoor or free-range certification represents a meaningful step above indoor equivalents.