Our 'Eggers coop' was stick built by DH and I. Elevated platform is 12x16 with enclosed coop being 12x12 with the roofed 4 ft porch. The porch is a wonderful spot and my favorite place to sit and visit with the birds.
Walls are insulated, eaves are open with sturdy hardware cloth to protect from varmits, windows were all free 'reclaims' from demolition projects we had stashed for later use, and actually so was the door, someone was replacing their old basement steel entry door and we snagged the old one.
There is expanded metal grating lag bolted over each window and a metal 1" bar that slides through 2 giant eye bolts on either side of the door and locks to provide 'bear security' since DH did find one sitting on the porch one morning!
General layout is step through man door into a people area which is about 3ft deep, to both right and left are deep shelves with broody hutches underneath of them. These are about 2.5 x 3 each and allows for stacking of as many as 4 broodies at a time in that area, though I think that only happened once, usually it is just 2 or 3. Then the main portion of the coop is one big open area, with the option of hanging fence panels in the middle to make it 2 smaller ones if needed. The fenced wall between the people area and coop has 2 doors in it so each coop would have separate access. The doors do not go to the floor, we leave a 10" or so step over sill so that when we go in and out a chick doesn't run out unnoticed. Little ones would have trouble jumping over at all and bigger ones get noticed doing it.
Each side of the coop has a pop door out into the covered run and the run can also be divided by adding a 10ft dog panel into it near the back corner which would provide a 300sq ft run or so to each coop.
A few pictures of the coop...