The don't do well in the heat or cold.i have them in Northern CA and if it gets into the 30s I give them a heat lamp. But, since you have a heated coop you already have that covered. For the extreme heat make sure you have a very well ventilated coop and keep them cool. They should not be able to fit through the chain link when full grown. But, they are great flyers. Good luck!
No worries on the flying the fence is 6 ft high and covered