Pigs lack functional sweat glands and rely on wallowing to regulate body temperature, making access to mud or water essential for their welfare.
Denying pigs access to wallowing opportunities in warm conditions causes significant thermal discomfort and physiological stress. Indoor systems with slatted floors provide no thermoregulatory options. Providing water misters, wet areas, or outdoor wallow access is a simple and effective welfare improvement that also reduces aggression linked to heat frustration.