Here is my chicken ark located in North Central Florida (Volusia County). It is constructed entirely of galvanized steel except for the wire around the bottom.
My previous batch of chickens was kept in a pole-barn construction coop made of Ondura and wire. I lost a fair number of chickens to the heat and did not want to go through that again. That old coop is now a storage shed.
I have had no indication at all of ANY kind of heat-related problems with this design. I keep it under a shade tree, and the chickens have the run of the fenced-in yard during the day. We lock them in at night to protect against predators.
We have 8 Buff Orpingtons living here.
I don't know why galvanized steel roofing is not more popular. I'm sold on it and will be building another one to raise chicks, and it will be built the same way. It is FAR easier and faster to work with than any other method I've seen.
More photos in the thread about ventilation http://www.backyardchickens.com/forum/viewtopic.php?id=5944&p=3
Edited by Colonel - 6/16/07 at 10:33am