All I know is what has happened to me. I used to keep pelleted feed in a metal trash can because of the mice. I also used to get moldy feed in the metal trash can that wasn't moldy when I put it in there. Also, a metal roof on an open air coop will sweat. I just put two and two together and found out that it really does equal four.
Maybe the silos have an air space between walls for insulation?
Maybe the silos have an air space between walls for insulation?