We are new to chickens and have 28: 10 partridge silkie bantams (turns out 1 cockerel that crows; how cute is that, the rest are hens), 8 guineas, 10 rare breed pullets. We did lots of research before starting our design plan. Our 3 coops were designed by my husband the architect based on, in no particular order:
Efficiency of use (coop cleaning, egg gathering, food and water refills) , rain/cold/heat /wind, attractiveness, exterior maintenance/upkeep, efficient materials usage. Each coop houses 8- 10 mixed poultry. After some research we found that it should face south to capture the most sun and heat in winter. And it will face away from the cold north wind). In summer, good wind flow through vents on east and west and south walls.
Since the chickens are free ranging they are out of the coop during the day for the most part. I like this coop because I don't have to "walk in" to it; I can open the big door and reach in to change food/water or gather eggs. I can walk in to clean it when I need to, there is good head room in the center.
The A-frame design drafts summer heat up from the lower vents at chicken level and out the top vents. It leaves the lower section cooler in the summer with good air circulation. There are roosts and 2 nests for the chickens to share. There is room to add a couple more nests if needed. The houseplan is made to use plywood sheets with minimal cutting. There are some interior wall studs and roof studs for support. Some trim pieces around top vents and door to give it a clean finished appearance.
The coop sits on cement blocks, giving the chickens a cool place to rest underneath or run for cover. This also puts the interior at my level when I open the door; I don't need a step. The chicken door has a removable ramp; at night I place it on the ground and secure the chicken door with a hook (on the outside of door) and eye bolt. When open, I placed another eye bolt to keep door up and open and put the ramp back in place.
I ran a bead of caulk along interior spaces where rain might leak or travel through inside (along the floor, at each lower corner, and around the vents) and then outside where there were gaps where wood panels did not meet exactly. Caulk was smoothed to blend in. The interior was not finished out in any way; we can do that later if we see the need. The exterior was all primed with Kilz first to protect the plywood from separating; then painted with an exterior enamel paint. The door was accent painted in grey.
The roof uses one roll of rolled roofing. The roofing just needs to be cut in 3 sections to fit width top to bottom. Cut plastic sheeting or scrap plastic and staple to the very top, overlap about 6" each side where roofs meet each other to ensure no rain leaks. Cut to fit width and install the bottom rolled roofing section first and nail down, then the middle overlapping it and nailed down, then the top overlapping it and nailed. We used flat flashing we bent over the center of the roof and cut just a little wider than the roof to give some drip protection to the vents.
My husband built the door to fit the narrow opening; we bought all our hardware at Habitat for Humanity outlet. Craigslist is also a great place to find low priced materials (look in the "Material" and the "Free" sections) such as plywood, roofing/shingles, paint, hardware, concrete blocks, etc.
We didn't put in any glass or plexiglass, but we can easily cut in and add some if needed, either in the front walls and/or front door to capture winter sun and heat, but would need an awning, out of scrap metal painted to match, to shade in the summer.