I love the CD answers...made me laugh, I bet those would work great in the pitch of a roof for wood peckers!! I need to try it, except I hate going up on ladders!!! I was wondering rachaelakers, if you could divide your bottom portion of the front door. So, another piece of wood framing, only not right up the middle necessarily, off a little to one side, or if that's too narrow, then right up the middle. Secure the new wood in place. Then the wiring you have, would be cut out. Buy some clear plastic that would be used for a runner on carpet. Not too heavy, but durable-ish.... (lol, new word) and attach the plastic across the top board , staple it on. You are basically making a "dog" door. The plastic has to be just a TINY bit smaller than the opening so it swings. The weight of it should just hang straight down. The "clear" would allow the chickens to see the outside through it, unlike a dog door, they are usually black. Dogs and cats don't care, trust me all of mine blast their way through all day! Now, for the times you don't want them out and for nighttime.... you would have to have a thin piece of wood to close. I would use a piano hinge, or maybe 2 small hinges and attach it to the wood frame, right side, left side, which ever way you want it to swing. Get some kind of little lock to use from the outside, obviously, so nothing in or out. The weight of the plastic shouldn't bother the chickens, but I would think, be too heavy for little birds!! The trick will be the weight of the plastic so it isn't to light and it blows around and allows little birds in. Don't bring the plastic all the way to the ground, looks like there is a board across the grass, but the shavings are over it. Might want to add a piece of wood across there for a little height also, to make it a little harder for the little birds to have to jump "up" and push in. Thinking of my dog door.... what they use to keep the rubber straight down is magnets, however, the frame work is metal so that helps to draw it closed.... so you might want to keep something like that in mind in case. Let me know if you try it or come up with something similar! Good luck.
