Right now I have my five chickens in two different setups. I have a very small coop with tin roof. I insulated the roof with some of the blue foam board and it makes a huge difference. I have an old refrigerator drawer full of sand on the floor of the run. I put large chunks of ice in it and two of mine love to sit in it to cool off. I also put ice in their water as you mentioned.
The chickens in a shaded pen -- I am misting down the floor of it during the hottest part of the day and putting ice on the ground. They also have a fan on them.
We are almost finished building our roofed run. We used to have a greenhouse, but had to leave it when we moved. I took the equipment out of it, though. One of the items was a PVC pipe misting system. I am planning to install it in the run which has a sand floor.