Their temporary coop has a wooden roof. We'll never know what occured - their permanent coop is almost complete and will have 3x the space. We don't know whether to shingle or put an aluminum roof on their 8ft x 12ft coop.
I suggest going with metal roofing of instead of shingles. There is a good article at http://www.cajunhomeimprovements.com/shingle-metal-roofing-best-warm-climates/, explaining why metal roofs are better for coops, even in warm climates.