"Contrary to popular belief, pigs are unable to sweat; instead, they wallow in mud to cool down. Their mucky appearance gives pigs an undeserved reputation for slovenliness. In fact,pigs are some of the cleanest animals around, refusing to excrete anywhere near their living or eating areas when given a choice."

https://www.pbs.org/wnet/nature/the-joy-of-pigs-smart-clean-and-lean/2126/