I'm also in TX - and heat has been the battle of the summers for me. I haven't lost one to heat yet - but I had one near-death-experience and another close call my first year of keeping chickens down here (about an hour south and east of San Antonio)110 F at worst but consistent 100+. I live in Texas.
Love your coop it looks really nice.
Quinlan - OMG - the home of Skidboot.... I love Skidboot and I think David Hartwig must be a genius with animals. I haven't seen anything quite like it anywhere else.