We have several empty Power Ade bottles, I think they are the 16-oz size, that we fill about half full with water and freeze. Every day about noon I top them off with water, put lids on them, and put a couple in each of the chickens' water buckets. If the water in the buckets is already warm I dump it out and put fresh cool water in, then I add these frozen water bottles. I put two water bottles in each water bucket. They usually help keep the water cool the rest of the day, and the chickens drink more if the water is cool. It really helps. It's been close to or over 100 every day for about two weeks, with no relief in sight.