Forgot to mention.......or maybe forgot if I did mention.......but those nest boxes are not fixed in place. They are just sitting lose on wall brackets. You can take them outside to clean them. Wire bottoms was an old school trick.......if you got mites.....you took the next boxes out and passed...
There are three intermediates they use to get to the roost bars. One is the bar just outside the nest boxes.......the second you can just barely see.....and that is a bale of hay I leave in there....future litter........but it serves as an intermediate step......the third is the rat proof feeder...
What you posted a picture of is a traditional, shed style coop. If you want half that size, here is a traditional coop that is of that style. The "Victory House", circa 1940.
These plans are available on a North Dakota State U. website, but are the same as shown above. The open front faces...
How big and what style of coop? Ideally, nest boxes are high enough a bird standing on the floor cannot see in, and roost bars elevated above the nests. Mine are 14" square, so are larger than what some use, and are elevated about 24" off the deck. Mine have wire bottoms to let the dust, dirt...