Pig Wallow and Thermoregulation Welfare

Pigs cannot sweat and depend on wallowing and shade for thermoregulation, making water access a critical welfare requirement in warm conditions.

Key Facts

Pigs lack functional sweat glands and cannot cool themselves by sweating
Wallowing in mud provides evaporative cooling and protects against sunburn
Outdoor pigs without shade in summer can die from heat stroke
Shade access reduces heat load equivalent to approximately 5-7C temperature reduction
Indoor pigs require sprinkler cooling systems in warm climates
Heat stress causes reduced feed intake, poor growth, and reproductive failure in pigs

Welfare Considerations

The pig inability to sweat creates a direct welfare requirement: active cooling must be provided in warm conditions. Outdoor pigs without wallow or shade access on hot days experience progressive heat stress leading to hyperthermia and death in severe cases. Indoor pigs need mechanical cooling through sprinklers or cooled air. The behavioral motivation for wallowing is extremely strong in pigs, and denying this behavior in warm conditions is both a thermal welfare harm and a behavioral frustration from inability to perform a highly motivated natural behavior. Best practice for outdoor pig systems includes multiple wallow points and shade structures.

What You Can Do

Support outdoor pig systems that provide wallowing and shade access
Advocate for cooling infrastructure requirements in hot-climate pig housing regulations
Choose pork certified under welfare schemes that include thermal comfort standards
Engage with pig producers about the welfare case for heat abatement