Ventilation with fans moving the air. Ice in their water. Frozen ice blocks with watermelon. Access to cool dirt to dust bathe in. Electrolyte supplements. Heat can be harder on Buff Orpingtons.
All of those prefab coops online are terrible and won't hold up for you very well. Best to repurpose or convert a shed and build a run. My husband built a great coop and run for me in our backyard orchard here in Roseville.
@Theladiesandagentleman
Me, my dogs Luna and Soleil, and the hens Myrtle, Poppy, Hazel, Daisy and Lilly. We are all the ladies that my amazing husband, the gentleman, has to live with. :love