Coop door design - how small can it be for large fowl? Automatic option?

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!

A very vague answer to the door size: a lot smaller than you would think!

I cut a "temporary" hole for our juvenile Javas at 6" x 6" in their nest/coop box and of course forgot about enlarging it. It's 3 years later and those poor (large) hens are still in and out every day, no worse for the wear.

I would be more concerned that a border collie could get through a 9" x 12" opening vs. a large feathered chicken. In my experience, the border collie would just figure out how to pick the lock on the coop anyways

It's easier to cut a hole larger than smaller! Personally, I'd go 6x6, or 6x9 and see what happens.

Automatic....lol It works, but most animals aren't patient enough, and the rest just don't get it. Except for the BC, he'd probably have it on a timer for "snacks"!

Just my experience though, hopefully others can enlighten us.

Make the chicken door 9 inches wide and 12 inches tall. Chickens can get thru and Fido wont. See the pop door on bottom left of picture. As for automatic pop doors. I like the Ador1.


I went out and measured mine.... It is 6 inches wide and 10 inches tall. My full size RIR have no problem entering and exiting.

You would be surprised how small a hole a dog will fit through, I don't take the threat of a dog getting in into consideration when making a chicken door I just make it however large it works out with the area and materials I'm working with the last one was 11 inches wide and maybe 15 tall then a make a wooden track and heavy door that opens upward with a pulley

Thanks for both of your ideas! If the door is 9" wide and 12" tall I am SURE my BC will be able to get in! She is a slight little thing and very motivated. Starting with a small opening and enlarging it if needed sounds like really good advice. I've seen videos online of trap nests with really short openings, so I know chickens can squish down short!

The automatic door I had in mind was something like the ADOR, open at dusk and closed at dawn. But, the ADOR is 13" x 10.5" aka perfect dog door size!!! But I suppose I could always put a piece of plywood or something like that over the top part, to make the opening only 6-9" tall instead of 13.

And yeah, it's quite possible that no matter what I come up with that crafty BC will figure out how to crack it! She'll probably just start nosing up the nest box cover and stealing them from the top or something!!! Her registered name is Desertshore Silver Fox - guess I should have known better than to give her such an auspicious name! Although I have had her longer than the chickens so who could have predicted this?

An easy test is to make an opening 6 x 10 in a piece of plywood, and see if BC is able to be squeezed thru such opening. Then if you decide to go with automatic door, make your opening in coop the size you want. Over that opening, install the larger 13 x 10.5 Ador1 . Nothing says both openings have to be same size. The Ador fastens to the outside.

MonicainAZ said:

Would chickens go through a door that was 9" tall x 12" wide?

Click to expand...

Mine is 9"x12" guillotine type I would suggested cutting it 8" to 12"off the floor.

The door can accommodate these birds with no problem (I think 9x12 will also accommodate a determined border collie).







I put a locking pin in my pop door to guard against predators fashioned with nail on a string or in my case heavy nylon whipper snipper line. The locking pin is drawn in to position by permanent magnet(s) inside the locking cavity in the frame of the door { I am currently only using one magnet on my small door}. You have to tie a not or a bolt to serve as a check once the pin(s) are drawn away from the magnet(s) against a bottle neck in order for the door to be pulled into position. I got magnet(s) from old speakers in a scraped car make an easy and effective locking device. My guillotine style door is raised and lower with this same type of line with just a small hole drilled at the top of the coop man door in my case. The reduced friction on this heavy monofilliment line means you do not have to bother with pulleys and the like. The pop door raises with little to no resistance with a gentle pull and falls with just the weight of the door which is made of of just ½"plywood. I hook the loose end of the line with a carabiner to the wire panels in the run in the open position and just unhook it and let if fall to the closed EASY PEASY.

We made our opening 12 inches wide and 18 inches tall because I tried to measure them and looked up the average height and wanted it tall enough for them to stand up and walk through and I remembered seeing on here once that the average height is about 18 inches so when you make shelves or the coop raised, etc. To make it at least that high so they can fit underneath. So we opted to just go with that for the door. The current coop door on the TSC kit is much smaller but the back door is about that size. We figured why make them have to duck? Most doors I've seen are 12x12 and that's fine but I figured it couldn't possibly hurt anything to go bigger, especially since some of our chickens are BIG. If you have a ramp it can be smaller because they walk into it but if they need to hop up or fly, you may want to make it a bit bigger so they can land and fit. Our ramp fell off and the pop door can't open all the way due to the chainlinl so we open the back door. They get up fine. New coop will have a ramp as well as being on the ground. Of course, 12x18 is rather huge and definitely the same size as some dog doors so no doubt a determined border collie could get through. Is there any way to keep her locked up or tied up so she can't get the eggs or so you can collect them first?

Not my original idea, but I saw a 'dog' resistant door that exploited the chickens ability to navigate tighter turns... Probably won't work with breeds like the Dachshunds that were purposely bred to navigate tight spots and turns but it should deter most other dogs...

A quick cut away sketch from overhead...



The chicken can be taught to navigate the maze to get into the coop, but the dog can't physically make the turns necessary to gain entry (assuming you don't make it large enough for the dog to navigate, height limitation being very important)...

I have a BJG pullet that could get through a 6x6 in a cattle panel coop I was building this winter, she was about 6lbs then.
I used to have a pet coyote and the dog house door I built him was 12x12, and 12 off the floor...he weighed 35lbs. It's now a small coop