Outdoor access for pigs provides welfare benefits including exercise, foraging, and sunlight that cannot be fully replicated by indoor enrichment, but requires management to avoid soil degradation and health risks.
Outdoor access transforms pig welfare in qualitative ways that are difficult to replicate with indoor enrichment alone. Soil rooting engages the full behavioural repertoire of a species adapted to turn over hundreds of kilograms of earth per day in foraging. Sunlight exposure supports vitamin D synthesis and circadian rhythm regulation. Exercise on uneven terrain builds physical condition and enables natural locomotor behaviour. Social dynamics in outdoor groups with adequate space are typically less aggression-dominated than indoor groups because subordinate animals have genuine escape options. However, outdoor access creates new welfare risks if poorly managed: inadequate shade causes heat stress, wet conditions cause foot and leg problems, and parasites require prophylactic management. Outdoor production that is well-designed and managed is not automatically higher welfare than optimal indoor enriched systems, but most comparisons show net benefit from outdoor access.