Comparing welfare outcomes across different pig housing systems from intensive to extensive.
Pig housing welfare assessment requires moving beyond simplistic ranking of systems toward evaluation of specific welfare outcomes in each context. Outdoor pigs can express rooting, foraging, and social behaviors that indoor pigs cannot, but face welfare risks from environmental extremes, ectoparasites, and predation. Indoor pigs on enriched systems with appropriate stocking density can achieve good welfare with lower disease burden and more consistent veterinary oversight. The welfare quality of any system depends more on management quality than system type — an outdoor system with inadequate shelter and healthcare can produce worse welfare than a well-managed indoor system with robust enrichment. Welfare science assesses outcomes rather than systems, measuring the actual welfare states of individual animals.