Set out to build a coop large enough to accommodate 4 or 5 hens and a rooster without crowding (basically enough chickens to keep the average family in eggs), small enough to fit in a pickup truck (because we'll eventually be moving), and light enough to move around the garden by hand now and then. Last but not least, I wanted it to last longer than I will. The base measures 4' x 8'. In order to use space efficiently, I built vertically rather than horizontally. There's a ground level, a roost level, and an enclosed shelter on top. All the wood in contact with the ground is pressure-treated. Everything else is pine or spruce with sealer on it. Every joint is glued, screwed and tattooed, as they say. Sharp edges are chamfered, more for me than the peeps. If I were starting over again, instead of siding both ends, I'd do just one end and one long side. That would make a stiffer structure and provide better weather protection, but there'd still be plenty of fresh air and sunshine.