Pigs cannot sweat and are highly susceptible to heat stress, making shade provision, wallowing opportunities, and water access critical welfare requirements for outdoor pig production.
Heat stress in outdoor pigs presents a welfare challenge that is increasing with climate change - periods of extreme heat that once occurred rarely now occur regularly across traditional pig farming regions. Pigs experiencing heat stress suffer acutely, with core body temperature rising and cardiovascular and respiratory systems under strain. The biological drive to wallow is extremely strong - pigs without wallowing access on hot days show persistent agitation and desperate attempts to find cooling. Shade structures and wallowing areas require investment and maintenance that some producers cut corners on. As summers become hotter and longer, baseline welfare provisions that were adequate historically are becoming insufficient without proactive adaptation.