I'd like to see the pulley systems people use to open the door from the out side. I put on on my pop door and it opens it fine. The problem is when I let it down it doesn't close all the way.
Ours slides up and down and is made from a cutting board. DH used some metal angle iron to make the slides so that there's no chance of wood swelling and keeping it from sliding easily. The pulley cable goes out to the outside of the coop and there's a hook out there so we can open and close it (and secure it open) from outside. We put a small board across the bottom on the outside and the door is inside of that so there's no way for any crafty critter like a coon to get their little fingers underneath and push it up. The first pic shows it from the inside and on the second pic you can see how the cable sticks out the side of the coop.