Our lean-to coop and covered run was built on to an old shed, and we currently have 16 young chickens and one chipmunk scratching about in there, but in the long run we expect to only have 8 to 12 chickens, and we'll have to see about the chipmunk.
The original "Old Shed" was just a small (12' x 18') rough cut oak shed/barn that my dad and uncle built when I was about 7 years old, with a budget of about $50 according to my uncle. We raised chickens, turkeys, geese, quail, goats, calves, ponies, and pile of kittens and puppies out of that structure when I was a kid.
When I was about 18 I built a lean-to onto the original building (approx. 8' x 18'), with scrounged materials, a skill saw, a hammer, youthful energy, and not much else. It lacked a lot, including square cuts and 90 degree angles, but it served as the chicken coop for my dad, off and on for years, as I was off living life in the big world.
In 2015 Dad passed, and the old place sat for a bit until we moved away from the city, in the summer of 2017. We built a new lean-to on the back of the original structure to house a tractor, and patched up and sorta' rebuilt the lean-to that I built 20+ years before.
Here is a shot of the old shed in disrepair (with some visiting deer) before we cleaned up around it and made modifications:
We live in the sticks and have all sorts of chicken eating critters to be concerned with, so we set out to build a secure, covered run. So we just took off the roof from the old lean-to and extended it out with new, longer metal, and added on to the end a bit. Eventually we'll add a bit more uncovered run space and/or let them range while we're out there with them.
The coop is about 8' x 8', and the run is about 3' x 18' along the lean to, and then opens up to about 8' x 12'... I think... you see there were plans, drawings, etc. ... but then I placed a post about a 12" too far out and had to improvise a bit.
Here is a "sketch" of the layout (not really to scale) :
And here are more "sketches" of what was planned:
And here is another shot of what we actually ended up with after all the plans, You can see all of the rocks we encountered when setting the posts and digging out for the buried wire apron. We had those laid out nicely and then an armadillo rearranged some of them for us recently.
Eventually I'll get around to painting the walls and doors to match, and adding the missing section of pickets... and maybe doing something different with all those rocks:
The picket fence is just a roll or two of garden fence attached to the 2x4 welded wire. I suppose it adds a bit of predator protection, but is mostly just for looks.
There is a buried fence apron that comes out about a foot or so, made of old 2x4 welded wire. The pickets also help hide the rather rough transition where the apron wire is tied into the new side wire.
The 2x4 welded wire should be adequate for predator protection for us. Since we don't have norway rats to deal with in our area, and long tailed weasels are not common. If a weasel shows up, I suppose I will have some loss, and then have to trap it.
We do have pack rats, aka wood rats, but they do not bother chickens, in fact I just trapped one this weekend that had moved in to the shed, and relocated it. More just to keep it from stealing feed and making a messy nest, ect., than a concern about it harming the chickens.
Snakes could get though the 2x4 wire as well, but I deal with snakes as they occur.
Our most likely chicken killer would be a domestic dog ( we have neighbors that let their farm dogs roam), and they occasionally come around our place, but not often. The 2x4 wire should be fine for keeping dogs out. But I have known determined dogs to chew through shed walls and porches, in order to get to a cornered critter. If one were to show up while we were away, and have the time to work on our run, i'm guessing it could get in if it really wanted to. But that possibility is a low concern in our particular case.
Our night time predator concerns are raccoons, possums, bobcats, and owls, and the 2x4 wire should be fine for those as well. Again a very determined raccoon could likely get in, but it'd have to work pretty hard at it.
I do set up a trail camera from time to time to monitor what's coming around and I look at keeping a population of chickens, much as protecting a population of wild fowl, in that it's best to do some management of predatory critters preventativly.
I've trapped to reduce "nest robbing" critters for years on several farms to help wild turkey & quail populations, and have trapped coyotes to help fawn survival, so trapping isn't new to me or something I have a problem with. In fact I have already removed close to a dozen raccoons and one possum in the first 2 months since the coop was built. And I think simply reducing the numbers of chicken eaters we have around the coop is a big part of keeping our birds safe.
Typically digging in is more a concern, so I used J-clips to attach a buried wire apron to the side wall wire, and then just a twist of wire to attach the picket wire to the welded wire. Here is a closeup, hope you can make sense of it.
I used galvanized lag bolts to attach the 2x4s to the 4x4 posts. You can see a couple of screws there as well, that I used to hold things in place so I could manage it by myself. We used ( a bunch of ) stainless steel staples to attach the welded wire to the 2x4s. I might come back with some screws and washers if the staples don't hold up over time.
There is wire running along the top of the side wall wire to keep a critter from pushing it in. Basically I cut the welded wire to fit around the rafters which worked well, but that left the top three and half inches of the wire between the rafters weak and able to be bent in. So I drilled a hole in the rafters, and ran tie-wire along the length of the run, and wove into the welded wire then j-clipped it to the top of the wire, so now it can't be bent in.
The inside of the coop is mostly reused or scrap materials. The roosts are re-purposed stair handrails, over some re-purposed wire panels (kennel floors?), the metal along the bottom was off the original lean-to roof, and the windows are the glass out of old sliding shower doors.
Under the roost area is the poop collection area that can be accessed from the outside for clean out:
Some detail "sketches" of the roost and clean out idea:
The inside of the coop walls are a mix of siding scraps, old re-purposed metal, and some of the original rough oak barn boards.
The lean-to is divided into 2 "rooms", one is the coop, and the other is mostly just garden tools and storage. In this second room along the dividing wall we have an old freezer in which we keep feed. This keeps out the mice, chipmunks, squirrels, etc.
I've added some "panels" cut from feed sacks just for decoration as well.
The door in the above image is pretty wide, with the idea of being able to park a wheel barrow there to clean out the coop floor litter when needed.
The door going from tool and feed storage room into the run is just made of an old re-purposed sheet of plywood, with a window cut into it, and some 1x4s to trim it out. The window is screened with wire, and has an old scratched up piece of plexi-glass that I found somewhere, that can be dropped down to let in a cross breeze to move some air through the lean-to.
In the picture below, the door is open with the plexi-glass lowered.
In this image the "glass" is up:
In the run there is a corner dust bath. Currently it's just a scrap board held in place with some firewood, on the front and some scrap plywood along the wire to keep the dirt in.
We added some metal signs as a bit of coop decor in the run... just for fun, and for something for the birds to practice their reading skills with :
I built a little "day roost" ladder with old wooden posts from a fence I took down, and a 2x4 cut in half:
Additionally I used a wooden post and 2x4 scraps to create an elevated roost in the run that some of the birds use. (see the dominique on it in the back ground on the left)
A nice piece of walnut limb that came from a blowdown of an very old tree currently serves as a "step" on which the birds like to sit, and/or jump up on the high roost.
And the naughty ones feel they must cool their feet on the waterer from time to time.
Years ago, I was driving by a house that had bench sitting by the curb, with a "free" sign on it. So I picked it up, and we just used it as a plant stand for container plants in the yard/garden for a long time. But now it's used properly as a bench for sitting and watching the chickens peck.
This is the covered "alley" along the original lean-to wall where the young chickens like to run and flap back and forth, and often lay in the shade:
And here are the birds crowding in for a picture, excited to know they'd be on www.backyardchickens.com