Wow, lots to think about! I like your ingenuity with re-using materials! If I hadn't just relocated I would be doing more of that! I think I will continue with my plan, but incorporate various venting options. The front was going to have doors for cleaning only but might as well screen them in also! I can always close them in! Since we seem to get an abundance of bright sunshine here I am incorporating passive solar into my design also.
Here is the basic design I am leaning toward. (couldn't paste the link, it is the Maxwell's house on the medium sized coop page)
Changes are size (either 6' X 10' or 8' X 10") and the main run this butts up to will be 8' X 18" and full height, 12" of it roofed. There is a 8' X 10" moveable run that can be rotated into three positions into the garden area before and after season.
I hope this isn't too confusing! Thanks to all for the advice and links! Hopefully I will be breaking ground in two weeks!