Ours like a nice pit of sandy loam in the shade they dig a hole and sit in the cool dirt. Some breeds take the heat better than others Cochins don't do well. Keep the shade plentiful and a mister doesn't hurt.
Yep. The other thing I take into consideration - I leave my chickens alone during the hottest part of the day. They get all excited and cluster around when treats are brought out, so I don't do that when it's hot. Left to their own devices, they'll rest in the shade.
I live in Tucson AZ and I am a first time chicken owner. I got 2 black sex-link chicks on October 1st and I have been worrying since then about what I was going to do when summer is here and it will be over 100 degrees most of the summer. Today it's 101. I finally figured out how to solve the problem. I bought a wire metal dog crate and put it against the doggie door so the girls can come in the house when it's hot and not poop all over the house then go back to the yard when it cools down. The dog doesn't go out when it's hot so he doesn't seem to mind his door being blocked during the day.