My duck house is built kind of like a small aviary. The ducks haven't moved in yet, but I plan on keeping them there at night without an enclosed coop. We made a chicken wire roof to keep hawks and raccoons out. The sides are chicken wire on the top half, but hardware cloth on the bottom half. Like you said, the whole thing would be hardware cloth if it wasn't so dang expensive. I REALLY wanted to have hardware cloth on the bottom half, though, because I read a story on the duck forum about a duckling who had its leg eaten by a raccoon at night. The raccoon actually reached THROUGH the chicken wire to get the birds and just ate what it could grab. Another lady was temporarily keeping her ducks in dog crates in the garage at night while she built them a coop, and the same thing happened- something snuck into the garage, reached through the bars and killed the ducks. (Though I don't remember if that one was a raccoon or a weasel.) I figure with my duck house if they climb up high enough to where the chicken wire is, they won't be able to reach anymore, especially since ducks sleep on the ground. One side of the duck house is up against a solid shed wall, so if I ever get chickens that's where I'll be putting their roosts.