Why bother with a plan? This guy started screwing things together, then cut off the overhands with a chainsaw. It looks better than most of my projects!
http://www.treehugger.com/green-architecture/chicken-coop-made-beer-cans-and-salvaged-parts.html
http://www.treehugger.com/green-architecture/chicken-coop-made-beer-cans-and-salvaged-parts.html