This is great information. I am in Southern Arizona and also deal with hot summers. I haven’t had the majority of my chickens during the summer yet. Very helpful.I'm in the Verde Valley. It's nothing to hit 110* in July/August up here.
Make sure the chickens have lots of shade and fresh water. As Rufus stated, mist the run several times a day. I even keep ice blocks, frozen milk jugs, or 2 liter bottles to put in the hen house and coop for them. They'll stand on the ice block and peck at it. You'd be suprised how much they will cool the area. I also freeze 16 oz water bottles and make sure to keep them in their water during the day.
Restrict their scratch. It's a "hot feed" and increases their metabolism to digest, causing their bodies to heat up. I also keep lots of watermelon, canteloupe, grapes, etc around for them during the summer months.
With a little additional effort on your part, they'll make it through the heat just fine.