backyardchickens.com was so helpful in our coop design, and we had so much fun during the whole planning and building process we thought we would share our experience.
We live on a 1/8 acre lot in a suburb of St. Louis. We have chickens for eggs and general entertainment. We wanted our coop to be handsome and functional, as we didn't want to have any problems with disease, difficulty in maintenance, or neighbor relations down the road. With a goal of about 10-12 chickens, our research indicated that we would need 2-4 sq feet per chicken. 4x8 didn't seem quite big enough, and so we went with 5 x 8.
We started in the fall, several months before we anticipated getting our hens, to allow us an ample number of weekends to prepare for the arrival of the hens.
First we leveled out an area in the back, and from my husband's ever increasing inventory of found, useful stuff, we used these round concrete cylinders as our footings. We built our frame, 14" off the ground, so that we can enclose the area underneath the coop for the chickens to have a nice, cool, shady place to hang out come summer time.

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Expert carpenters may wonder at certain quirks in our framing techinques, but we sort of designed as we went, making mistakes and then compensating for them--so though our building may not be the most elegant or efficient, it is quite functional, and worked out in the end.
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We nailed a sheet of fiberglass on top of the plywood floor. This will lengthen the life of the floor, protecting it from moisture, and making cleaning much easier.
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We built the frame to allow for a large vent on the back, as most advise on good airflow during the hot months.
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Nest boxes in the front.
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This is the "people door" side. I (that's me on top) chose the height and angle of the roof by standing so that at the peak, which was forward of the middle, was tall enough for me to walk through. I'm 5'4" tall.
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So, here's the first thing I wish I hadn't done. My husband has a plethra of old french doors in the basement, just taking up space. Originally, during the planning stage, I had decided to use one. For some reason, I forgot about this descision, and I purchased these two windows. They are fine, but I wish now, that I had used a door.
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My husband saved the pine panneling installed in the 1970's era addition of our home. This room was turned into a kitchen. The knotty pine went to the basement. We thought this would be a perfect way to side the building, because the pannels fit snug together.
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We used architectural shingles, with brown tones because we didn't want to have to look out at an unattractive roof. Unfortunately, the size of our roof was a few shingles too big for just one bundle of shingles, and we had to buy two bundles. We installed a vent at the peak. My husband, still recovering from a broken leg, was unable to climb up, so I was on top with the hammer and roofing nails. I have a new appreciation for the roofer. Also, we used 1/2" plywood, and I wished we had either used thicker wood or shorter nails. We spent an hour clipping off sharp nail ends on the inside of the coop ceiling.
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Because of the savings on labor, and our limited supply of pine boards, we used a pressure treated faux paneling plywood on the back.
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A pulley system to raise and lower the window.
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A close up of nest boxes.
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The beginning of the run. The upright posts are new felled cedar, which are free when you have someone who lets you cut them off your land. To keep things simple, and because we were running out of time, we went ahead and used treated 4x4's for the top of the frame of the run.
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The chicken door, also uses a pulley system.
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The wire tunnel from the run to the coop. Unfortunately, when I put this up I didn't realize I shortened the door height. So far, the chickens don't care, but they aren't fully grown. We may have to adjust this in the future. We still plant to close in underneath the coop, and put another tunnel on the back side of the tree.
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A few final views....
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The girls love thier various perches. Often, I will bundle up greens, rubber band them together, and stick them in to the wire fencing, with a stick holding them. The girls LOVE salad.
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Thanks for viewing! Good luck on all your chicken endeavors!