I'm looking to build a duck coop that my ducks can fly/get into but is also predator proof. I have chickens with a predator proof run because I don't want to forget to lock them in at night and loose my whole flock. My local predators are raccoons, red fox, and coyote. I'm wondering if I can build the coop on posts so it is 4'-5' high to the bottom of the coop and door and wrap the posts in smooth sheet metal so they can't be climbed. Will this work or does someone else have a better idea? I have a ditch around my yard with water most of the year so they would be much happier to have access to my yard rather than be locked in a coop and run all day.