Give them a wading place to cool their feet off. I use a 4" deep lid from a rubbermaid like tote. They love it, use it a lot and it's easy to change the water a couple times a day to keep them interested. They drink out of it too when they wade, yuk, but it helps them drink more, stay hydrated, cooler, happier. Also, you can Tie out a tarp on the sunny side of their run, to shade the ground next to their run, so not so much heat is reflected into their pens. Try not to cut off the breeze, just shade as much ground as possible. Hope he's feeling better soon.