Pigs have an innate need to wallow in mud or water to regulate body temperature and skin condition. Denial of wallowing in intensive systems is a major welfare concern.
Without wallowing opportunities, pigs suffer heat stress and skin problems, particularly in summer. Motivation studies show pigs work hard to access wallow facilities, indicating high welfare priority. Provision of cooling water sprays or mud wallows in outdoor systems significantly improves welfare. Indoor systems should provide cooling mechanisms to compensate.