I freeze water bottles and plastic milk jugs. Place them in the nest boxes. I have a small wading pool with 3 inches of water in it. Most of the girls will stand in it and cool their footies. I have a couple that don't, but they are the minority. I water down the run, so that when they take their dust baths, the dirt is cool and slightly moist. Have a vent fan in the coop and I have shaded the windows. Egg production is down, but heck, I don't want to work out in this heat...I'm sure they don't either. In my mind, this heat is reason for an egg strike.