It seems to be the season for chicken coops, so I thought I'd post a few of the construction of mine. I made it largely from scrap and extra materials I had laying around. I decided to insulate it a bit as it can get both hot in summer and cold in winter here. I did not air seal the rear egg box hatch, I do not close the front door at night and the chickens have shown no sign of any cold stress in the last two winters.
Basically I built a simple frame from 2x4's and pressure treated 4x4's and press fit/screwed some 2" insulation in. For the front door I cut the top off an insulated door that was leftover from the greenhouse which had a window that now doubles perfectly as a chicken entry door. Almost the whole front swings open on the original hinges that were part of the insulated door (I think it might have been a door built for a mobile home). I did put plywood/T111 over all the insulation in the interior so the chickens would not eat it. I had some greenhouse multi-wall plastic that I used for the triangular side windows.
Once the main house was built I bolted it down to some skids so it could be pulled around and made a little screened in area/yard for times when I want to keep them penned up.
It's worth mentioning this design has worked really well. I think the original build was in 2008, it's now 2014 and it's still working great. The insulation keeps eggs from freezing when friends with uninsulated coops are having breakage. We may re-side it with some leftover hardie plank from the house to make it match. The front screened area has failed, the turkies liked to roost on it and it was not designed with a 200+ pound load of turkey on it.