I've only had chickens a little over a year and last year way very hot/humid, we had feel like temps in triple digits. I was beside myself watching them trying to deal with it. I had the shade tarps and fans running. I hopped on the pc to see if there was anything I could do and that was when I learned chickens cool thru their feet. The only viable item I had on hand was a tray that was 16" across and just over 2" deep, I had several of them. I put them in the coop and put the first hen in it, she jumped out, the second hen jumped out, the third hen didn't jump out. They're in and out of them many times throughout the day.  I toss in a frozen water bottle and they're happy to have them and so am I.