Here's my 8'x8' coop and 8'x16' run. I used 4x4 treated posts in the corners, 2x6 treated floor joists, and 2 sheets of treated plywood for the floor. 2x4's finished the framework, and 1/2" shop siding covered the exterior. The run is made of treated 2x4's I ripped into 2x2's, and covered with 2"x4" welded wire.
Front section of coop (3'x8') is for storage and egg collection.
Ladder-style roost is on a pulley-type system so it can be raised for easy clean-out. Door below roost makes for easy clean-out by simply pushing bedding out.
Diagonal roosts are removable if needed... but I haven't needed to since they're not in the way of anything.
There are two sliding panels on the rear (right and left) that can be adjusted to control ventilation. It's winter, so they are mostly closed to reduce drafts. Plywood creates a natural buffer between ceiling and tin roof to keep things cooler in the summer.
There is also a flap on the front that can be opened in warmer weather to create cross-flow.
The pop door uses a pulley-type system to open and close without having to enter coop or run.
To save time and a lot of labor, instead of digging a trench and burying wire underground to keep critters out, I opted for a set of Solar Nite Eyes. I have one mounted on each corner of the coop and run, and though we have lots of foxes, coyotes, raccoon, opossum, etc., nothing has attempted to dig under the fence. I highly recommend these!!!