Outdoor and free-range pig systems, including farrowing outdoors in arks, can provide significant welfare benefits compared to confinement systems when well-managed.
Outdoor farrowing allows sows to express one of their most strongly motivated natural behaviors: nest building before birth. A sow who can collect material, root, and construct a nest in the hours before farrowing is fulfilling a deep instinctive need — the frustration of nesting motivation in confinement is clearly stressful. Free-ranging piglets develop more robust immune systems and show less fear of novel stimuli due to environmental complexity. The welfare benefits of outdoor systems must be managed carefully, however — piglet mortality from exposure and crushing can be higher where stockperson skill and monitoring are inadequate, requiring attentive husbandry to realize the welfare potential of outdoor production.