I live in south texas and extremely hot and humid weather. I have an open air coop type of coop that I built, yet that still didn’t cut it as far as chickens overheating. I invested in fans made specifically for dusty areas(think horse barns). I have 3 of these going full blast 24/7, I go out in the heat of the day and put the hose inside the coop and let it soak and entire area, and find that many hens will lay down in the wet area to cool off. I tried the whole frozen water bottle thing, however I have too many hens and I don’t have enough space in my freezer to freeze that many water bottles I would need for the number of chickens I have.
this year I have ordered another fan. I like the fans with sealed motors either Max Air or Tornado brand. These are the industrial ones that put out a lot of air, but also much safer for the area i have them in.