Here in North Carolina it gets hot and humid and stays this way....90ish for days at a time and my girls are about 12-13 weeks old (Cream legbar ladies) and they have panted some. I keep small water bottles filled and Frozen.
When i refill their gravity waterers i put several bottles with caps removed UPSIDE DOWN in there. The water stays cold and as it melts it runs out.
Another trick i discovered is to put a small plastic bowl of ice water inside a clay pot, (they like a sprig of peppermint in it, we call it their peppermint tea) the clay holds the cool a little longer and they can't tip it over. Use a short squat pot. I push straw or shavings up around it in a shady spot for increased insulation. Seems to keep them sipping