Our farm used to be a small-scale commercial pig unit, with concrete runs so no chance of a wallow. The pens do have a hose connection nearby and over the last week we've been showering the pigs (up to 8 times a day for the pregnant ones). They stretch out and "uff" at me with happiness and then we run the water over the concrete too, to cool the area as it evaporates. It's been 34 degrees on the yard some days.