I'm not sure how many total chickens and turkeys I have just now. Should be around 100 or thereabouts. I don't set up misters, feed them frozen watermelon, or put ice in their waterers, but I've never lost one to heat.
What I do provide for them is shade, good airflow, and plenty of fresh, clean water. Those are vital and without them you can lost birds to heat. My chicken tractors are open all the way around the bottom so they can always be in the breeze. Everyone has shade to get into and I refill their waterers at least twice a week. The growout pens are very full right now so theirs get refilled every day.
They'll spread their wings, pant, eat less, and so on, but that's because it's summer. In the mornings and evenings they'll be active. In the heat of the day in the afternoons they'll lay around like anyone with any sense would do (only mad dogs and Alan Hagan go about in the noon day sun at my place!)
Folks have been keeping chickens in Florida longer than any other place in the United States. They're hardy creatures as long as you give them shade, air flow, and water.