Why pigs need mud, not just water
Pigs cannot sweat, so on a hot day a wallow is their cooling system: they coat themselves in wet mud, and as the moisture evaporates from the mud it draws heat from the skin far more effectively than shade alone. The mud layer does double duty as sunscreen and insect protection, which matters most for pale-skinned pigs whose ears and backs burn quickly in strong sun. A pig with access to a good wallow will spend the worst heat lying in it and emerge plastered; a pig without one pants, stops eating and can overheat dangerously on still, humid days. Providing both a wallow and proper shade is not pampering — it is the basic summer kit outdoor pigs need.
Digging and siting the wallow
Choose a spot on ground that holds water without draining straight into a gateway or drinking area, and near enough to a tap or trough that refilling is easy — a wallow nobody can be bothered to top up dries out within days. Scrape or dig a shallow depression, roughly a body-length across per pig with room for the whole group, and no deeper than belly depth: pigs want to lie in it, not swim. If your soil is very free-draining, puddling a clay lining or sinking a large shallow liner helps the mud hold. Keep the wallow a few metres from feeders so spilt food does not sour in the mud, and expect the surrounding ground to get churned — a hardcore or slabbed apron on the entry side saves the worst of it.
Shade that works all day long
A single tree shades one moving patch, so check where the shade actually falls at midday and mid-afternoon, when heat peaks. Many keepers add a simple roofed shelter — a low open-fronted ark, or a tarpaulin or shade cloth stretched on posts over part of the pen — positioned so some ground is shaded at every hour. Site the shade near, but not inside, the wallow, so pigs can move between mud and dry shade as they choose, and make sure there is enough shaded room for every pig to lie down at once: the lowest-ranking pig gets pushed out of both wallow and shade if space is tight, and she is the one who suffers silently.
Keeping the wallow healthy through summer
Top the wallow up with fresh water daily in hot weather, and give it a proper refresh — bail or drain the worst of the soup and refill — whenever it starts to smell sour rather than earthy. A wallow should be mud, not a stagnant slurry of dung: site feed and dunging areas away from it and pigs will mostly keep it clean themselves. Check pale pigs' ears and backs for sunburn even with a wallow, and watch for any pig that stops coming to feed or lies panting away from the group, as heat stress can escalate quickly and a pig that is collapsed or distressed needs a vet the same day. Through the hot months the daily wallow top-up is the job that gets forgotten, and KinsLe's Family Sharing helps the whole household prevent that — the pigs' summer routine, including who checks the mud and shade, sits in their shared profile so anyone at home works from the same notes.