Shade is your best friend. If you can move the coop to a spot with natural shade, consider doing that. If you can't move the coop and/or don't have natural shade, create some artificial shade with a shade tarp up above the roof of the coop and on the side that gets afternoon sun.
There are some good ideas for how to do that on this page:
I am in Florida also and we are now getting temps that are well into the mid 90's by afternoon. During the day the coop is just too hot. The only solutions that I have found are, one, that I have a covered run that is open. Once it starts to get hot I turn on a mist system that operates in about 1/3 of the run and at mid day when it gets very hot they do like to be near the mist as it drops the temps at least 10 degrees. I also have a ceiling fan in the run that does circulate the air and also speads the mist around. I have a shallow pan that I fill with cold water that can can step in which also seems to cool them a bit. Most importantly you need to make sure that they have a constant source of cool water at all times. During the afternoons I will usually cut a quater watermelon and put that in their run. They love it and it provides them with water. If yours are confined to their coop during the days then it will be very hard to create something that will keep them cool enough when the temps hit the high 90's.
You can find a free ebook on google called Open Air Chicken Houses...in hot climates, you need mainly wire with maybe one or two walls to block high winds, etc...it took me less than an hour to read it..it was written about 100 years ago..great book.
Just went shopping for mister ideas--home depot here is out of mist appliances so we went next to Northern Tool off I20 & Great SW Pky. Got a cool (literally) mister attachment that zip ties onto a fans wire front for 12 smackers! Bought their small black wire front fan for 29, and walked out with a non-oscillating outfit for under 50 bucks!
The mister might fit any fan like a box fan or other you have already. We only had a big box fan but for garage cooling, so another fan was needed. Works fabulous! might sit with chickeys just to enjoy the mist myself!
thout you all would want to know!