Wow, that's your first try building something like that? It looks great!
The only thing I would add, is painting the inside with several coats of outdoor paint. This will fill in all the tiny crevices where mites and lice like to hide.
Great Job PeeWee. How many pallets did you need to complete the coop itself? I love the idea of screwing the 2x4's down and being able to sweep it out. Brilliant.