Pigs are highly susceptible to heat stress, suffering significant welfare consequences in intensive systems as global temperatures rise and ventilation systems struggle to cope.
Heat stress in pigs causes genuine suffering: panting, restlessness, reduced movement, and in severe cases heat stroke and death. Sows in gestation crates cannot move to cooler areas or engage in wallowing — behaviours essential for thermoregulation. High-welfare systems providing shade, wallowing opportunities, and sprinklers significantly reduce heat stress indicators. As climate change drives more frequent and intense heat events, the welfare burden in inadequately ventilated intensive pig units will increase substantially. Breed selection favouring rapid growth has also reduced pigs' heat tolerance compared to slower-growing heritage breeds.