I have several things that I do here in Arizona. I freeze 2/3 of their water in their waterer and fill it with water the rest of the way, that usually keeps their water cool for most of the day. I will switch it out with the extra waterer that I have also put in the freezer when the water gets too warm. I also freeze 2 liter bottles and put them in the pen for them to lay against. Just make sure you freeze them with the tops open so you don't have an explosion. They also like it when I fill a ziplock bag with ice and put it in their pen. I have come out several times to see them "roosting" on the bag of ice to keep cool. I hope this helps. I try to avoid misters, because I don't want to promote mold.
BTW it is 108 here today!
Chrystal