I can tell you the best way to prevent it but I can tell you how I prevent metal roof condensation... 2 vents. One vent is the entire length of the highest wall about 6 inches tall right up at the roof. then the exact same thing at floor level on the opposite wall. That way intake and outtake vents are on complete opposite ends of the coop which leads to most moisture leaving. Thats not to shoot down other suggestions which are good too. Thats just how I prevented that issue. But that might just work in my climate as I do not deal with temps that go below 10 degrees.