We converted an old doghouse into an inexpensive coop.
We started with a used doghouse. It has a solid wood base, particle-board walls supported by 2x4s, and a heavy, shingled roof that lifts off. The roof takes two people to safely lift it, so we figure it's pretty secure.
Windows cut in both end walls. 2x4s lift the roof about 6" for year-round ventilation, cut with the same angle as the end walls to keep the pitch on the roof.
The interior of the walls lined with rigid insulation and "finished" with plywood. A small door for collecting eggs is cut in the back wall, attached with hinges and secured with a latch. The chickens' door is the existing dog door. In the winter, a hinged door will be used to keep the coop warm at night.
Perches are tree branches from a recent trimming project, held with brackets of scrap wood. Hardware cloth is stapled to cover all openings. The entire dog house, which looks more like a chicken coop at this point, is painted it inside and out with a gloss latex paint to make cleaning easier.
Coop attached to the run/raised garden bed with access door/chicken ramp on the end.
Thanks for reading!