Here are some photos of the tiny coop i built for my aunt's tiny "kikikirikis" rooster and hen. Its size os 2'x2' floor it has a roosting space over the nest . Both the top of the nest and the nest itself later were lined with hay . The space is quite confortable for the lovely couple of pet chicken. Those pics where taken before we built the outside pen. So we just attached the cage to de coop door temporaly. Materials used : 1 and a half wood panels ( 1/2" × 4'×8', 4 wood pieces 2"×2"×8' , 4 furniture "legs" from homedepot, a piece of repurpose chackboard and asphaltic roofing material, screws, nails, staples, paint and 6 linoleum tiles. Cost around US$80 in materials and took me about 40 to 50 hours of work as I don't have many tools.
I draw some plans in PowerPoint but Im creating this article in the cellphone's BYC app and i am not sure how it works.