Outdoor access for pigs dramatically improves welfare outcomes, allowing natural rooting, social exploration, and behavioral diversity that indoor systems cannot provide.
The behavioral enrichment provided by outdoor access is qualitatively different from the substrate provision possible in indoor systems. Genuine soil provides infinitely varied olfactory and tactile stimulation that pigs explore for hours. Social behavior in larger outdoor groups is more stable and less aggressive than in high-density indoor housing. Wallowing in mud is a critical thermoregulation behavior that also protects skin and provides parasite control. Pigs with outdoor access show behavioral indicators of positive affect including play behavior and exploratory motivation that indoor systems cannot replicate.