Welcome to the world of chickens! As far as the heat, it got awfully hot up here in Northeast Texas this summer (110+!) and I and out of close to 100 birds at the time, I only loss two chickens to the heat. One was a Broiler that my daughter adopted, and as such I wasn't allowed to process and the other was a Lakenvelder (golden) I'm pretty sure that heat wasn't a factor in the broiler as poor Shelley was 5 months old and quite a big girl (it could have exacerbated her problems though), and I can't say definitively that it killed the other Lakenvelder as her 3 other sisters weathered it fine. When it gets hot, just provide them with good shade, plenty of ventilation, and in extreme heat ice (I filled up old 2 liter coke bottles with water and froze them then threw out in the chicken run for them), and even in Texas, most breeds will be fine! Best of luck!