So, I have an interesting coop design consideration. My chickens are in my urban backyard, and after some acclimation they are at the point where they are fine to free range in the yard when the dogs are out, so I'd like to be able to let them out more frequently. So far I've been just leaving the coop door open, which lets the chickens come and go as they please, which is working great for them. The problem is that my younger dog (border collie) has figured out that the "egg song" means free snacks! The little stinker climbs up the ramp, goes into the coop and steals the eggs. I've been inside the house and as soon as she heard the chicken singing, she went right out. The hen was still sitting on the nest so she barked at her! She also sometimes helps herself to the chicken feed. Having a smart dog is great but I didn't need that smart, lol. I'm just glad she's nice to the chickens! My setup now is a 4x12 run with a 4x4 coop, and one 'human-sized' access door. My thinking is to put in a smaller door to access the run that is hopefully big enough for the chickens, but too small for my 40 lb dog. It would be great as well if it opened and closed automatically, although that's not a requirement. So, how small can the door be and still allow my big Australorps to go in and out? I am thinking especially about making the door pretty short, as I'm not sure I can make it narrow enough as the dog is pretty narrow also. Would chickens go through a door that was 9" tall x 12" wide? Also, does anyone have any experiences with adding a door motor and timer to a pre-existing door? I've looked at a number of the automatic door designs and they look great, but they are all easily big enough for a sneaky border collie! Thanks for any advice!