Hey Bird.....Good question! It's been very hot here in Ohio, and humid too. Most of our summer has been in the upper 80s and 90s, and the humidity has been terrible. I'm not sure what area you are from, but during this hot weather. I do provide LOTS of cold water, and sometimes cool treats like watermelon, cantalope, cucumbers and tomatoes that have been in the fridge. It helps them cool off. It's normal behavior when a chicken gets hot, to breath with their beaks open, and they also will hold their wings out from their bodies to help them cool off.
If it's even hotter in your area, you can put a fan in your coop this time of year, and even mist your hens with some water. But really, you're doing everything right....providing shade and water.
I do put extra large water containers in my coop, and since my chickens free range daily, I put a large plastic dishpan out in the shade for them, and I save cool whip containers, freeze water in them, and put the big chunks of ice (giant ice cubes really), in their water outside.
Hope this helps!