Here is a small 6 ft. X 4 ft. X 6 ft.tallchicken coop that I added on to my existing 18 ft. X 8 ft.X 8 ft. tall ceiling heightstorage shed. This allows enough room for 6 regular size hens (Rhode Island Reds) without stressing them and causing related problems like feather pecking.
I have provided 2 nesting boxes built on to the outside with exterior door access so my familyand I can gather eggs without messing up our shoes.
The coop is insulated (floor, walls, and ceiling) however, in retrospect, I probably wouldn't do that again even though the winter months can sometimes be quite cold and windy in our climate. There is a small ventilation window provided onone wall with a sliding closure pane if necessary. A soffit vent in the eave provides venting through the atticwith the attic access door in the ceilingmade out of 1/2" wire screen. Also, a screen door is provided along with the "people" walk through door so the solid door can be latched open and allow venting that way also. We usually always leave the solid door latched open so we can view our girls from the house. The only time we close the solid door is when it rains or on bitter cold(below freezing) winter nights.
I purchased a remnant of vinyl flooring from a local supplier to completely cover the floor which makes for easy cleaning plus provides a waterproofing measure for the floor insulation under the decking.
The coop is wired for electricity and I use some artificial lighting with a timerin the darker winter months togive the girls about 12 hrs. of light. I also provide a small 40 watt bulb with a covered, rain tight fixture in the pen by the chickendoorway to let the girls wander into their predator proof yard in the early morning hours so they can have a little more breathing room.
Our coop opens up into an outside pen that is about 18 ft. X 4 ft. X 6 ft. tall. It is bordered on one side by a wood privacy fence, one side by the storage shed wall, and on the 2 ends by 1/2" square opening wire mesh with a entry door/gate for people. The top is covered in chicken wire.The bottomperimeter is lined with used railroad ties that are buried in the ground flush to the top.
In closing, all I can say is it was a labor of love to construct all on my own. It took a lot longer to build and cost more than what I originally thought it would but I think it's going to last a long, long time. The hens seem to really like their living arrangements a lot!