Open and cover with HC as much as possible. Maybe cut another window into the side as well. All windows open in the summer. Screen door will help, too. In the summer, the temperature inside will probably still be higher than the outside, but the more area you have open, on different sides, the more air movement and cross breezes there will be to help with the heat. May need multiple fans, too, to get air moving.
Our summers get HOT despite being farther north than you. I have a thermometer in the coop and the temperature in there gets above 100 and stays there even into the night, even though it rarely breaks 90 outside. It's this hot despite me opening a ridiculous amount of vents and windows. The tops of all my walls are open (6" tall openings wrapping around the whole coop); I have two shed windows that are open all the way, and a HC screen door for human access, plus two clip-on fans - one blowing across the vents, and one blowing at the roost. And the coop is under trees. It all helps, but the temperature is still 10+ degrees hotter inside than it is outside, and the chickens pant at night... So, in preparation for real summer, open as much as you possibly can.
Our summers get HOT despite being farther north than you. I have a thermometer in the coop and the temperature in there gets above 100 and stays there even into the night, even though it rarely breaks 90 outside. It's this hot despite me opening a ridiculous amount of vents and windows. The tops of all my walls are open (6" tall openings wrapping around the whole coop); I have two shed windows that are open all the way, and a HC screen door for human access, plus two clip-on fans - one blowing across the vents, and one blowing at the roost. And the coop is under trees. It all helps, but the temperature is still 10+ degrees hotter inside than it is outside, and the chickens pant at night... So, in preparation for real summer, open as much as you possibly can.
