Different pig housing systems — from fully indoor intensive to outdoor free-range — produce different welfare profiles, with no single system being superior across all welfare domains.
Comparing pig housing systems for welfare requires recognising that each system involves trade-offs between different welfare domains. Outdoor free-range systems allow rooting, wallowing, social freedom, and expression of natural behaviour — significant welfare advantages. However, outdoor pigs are exposed to thermal extremes, predation, and higher parasitic burden than indoor animals. Fully indoor intensive systems on concrete fail across multiple welfare domains — inability to root, social restriction, environmental poverty — but may have lower disease and mortality risks than poorly managed outdoor systems. Indoor enriched systems with deep straw bedding represent a potential middle ground, providing significant enrichment that allows rooting and social behaviour while protecting from weather extremes. The most welfare-honest approach assesses individual farms using validated outcome-based metrics rather than simply assuming housing type determines welfare. A well-managed indoor enriched system may outperform a poorly managed outdoor system across multiple welfare indicators. This complexity should not be used to avoid driving up standards, but rather to pursue genuinely high welfare outcomes regardless of the system used.