About midsummer the 4th year I started putting it together. The framing is 2x6s on the lower floor and 2x4s on the stub walls topside. Rafters are 2x6s. Studs and rafters are 2' on center with purlins also 2' on center. Joists are 2x6s 2' on center and the beams are 2 2x8s bolted together. Center post is a oak 4x4. This is all free lumber disregarding my labor which is free to me. I did use treated 2x6s for the bottom plate to guard against rot. The siding and roofing is all used steel roofing purchased at a local salvage yard. I saved well over $1000.00 by going with used steel. With 3 foot stub walls on top with a 7/12 pitch roof I have ample head room and more storage space for hay than I'll ever use. The steel needed a little work cleaning and caulking holes. It straightens right out and looks great with a coat of paint.
I purchased 8 large thermopane windows for a dollar each at a local auction for use in the coop. Six are facing south for solar heat in the winter. I made the doors for the loft with 2x4s and 3/8" plywood. The ground floor door I made with a 2x2 frame and 3/8" plywood both sides. Sandwiched inside is 1 1/2" rigid foam insulation.

The coop does not have electricity and I do not plan on wiring it. Before rural electrification and even after, farmers rarely had coops with electricity. Chickens got along just fine without it for hundreds or thousands of years and I figure mine can do just as well. I have to thaw out their water in the morning most mornings when it's very cold but they are fine waiting for it. I use a old-fashioned oil lantern if I happen to check on them at night. This works great. It gives adequate light and does not frighten or startle the birds. This also allows me to hang the lantern if I need to get anything done and gives steady light where a flashlight needs to be held or is seemingly always pointed in the wrong direction.
Details: I have one large vent in the loft. The ceiling boards are 3/4" popple with gaps around 1/4" for ventilation through the straw. The inside walls are covered with salvaged roofing steel. I used fiberglass insulation for the walls instead of wood chips treated with lime as originally intended for insulation. Time became an issue and forced this decision. Roosts, nests etc. have been built according to information gained from BYC and all is working to perfection! The floor layout can be altered according to needs with temporary partitions. In the spring and summer months I partition off about 1/4th of the floor space for a brooder area. The young chicks are protected from the flock in this way. By the time they are let loose into the flock they are well acquainted from seeing each other through the chicken wire and there are no squabbles. This partition could also be used for breeding purposes. One of the three pop doors exits from the partition room if I choose to let the youngs ones out all by themselves.
All my chickens did very well in the coop the first winter. It was a very severe winter (even for Minnesota) and was a good test for my planning and designing skills. I had no problems whatsoever with drafts or condensation. We had a high of around 90 chickens in four age groups the second summer. These are mostly mixed breed dual purpose birds. Most will be going in the freezer keeping around 20 or so over the winter. I feel the coop will accomodate 100-120 during the summer months. It would accommodate 40-50 easily during the winter months but I do not plan on keeping more than 20-30 over-winter.

That is the story of my chainsaw coop. A good job done and working to perfection!