Shade and water. When it’s hot, the most important things to provide for the birds are shade and water. Thankfully, there is always a part of my runs which are in shade. There are a few hours during high summer afternoons where the trees cast no shadows in the runs, but the coops do so there is respite. Rosie’s section of the run had no shade, but the tarp which keeps the rain off of her coop also blocks the sun during these hot afternoons.
Chickens, like dogs, do not sweat, so they pant. You’ll also see a hot chicken holding its wings away from its body to cool down.
I usually just have one nipple waterer hanging in each coop, but when the days are hot, I like to provide a few tubs of cool water to drink or wade in. I also like to mix their food with cold water to present as a mid-day treat, and I change their water more often.
They love the shade under their coop and often dig down to find cooler dirt. Mama Rosie is actively digging to make a cool place for her and her chicks to sit on this summer afternoon.