I see everyone using different things as nesting boxes. I have one made out of ply wood and I'm looking into revamping my coup in the spring time. And have started looking into getting milk crates and will add a lip to the front to keep eggs from being rolled out. I have read how metal is best wood is ok but can harbor bugs but that I see how people use a five gallon bucket. So I think milk crates should work as well. Does anyone see this a failed idea?