Here's what we use, and how many we use depends on how hot it is.
-Fresh water 2-3 times a day so that it does not get hot.
-Add ice to water dish
-Feed cool snacks like melon, frozen veggies, extra zucchini, etc.
-Put a stainless steel feed dish in run, and fill with cool water for them to wade or sit in
-Freeze water and chopped treats like veggies and fruit in pie tins to put out in the run. They'll peck at it for awhile to get the treats.
-We put a pop-up tent over them for shade since they are in an ark.
-Put mister on pop-up tent with a timer to go off every hour for 15 minutes or so.