There are some basic rules for designing and running a good healthy chicken shack:
1. Adequate floor space per bird.
2. Dry with good ventilation.
3. Temperature control.
4. Predator protection.
5. Keep it clean + fresh water/food = happy & healthy birds.
Many towns actually allow up to 5 chickens but no roosters. Check local rules on this if you plan to build. If you do get chickens in town, be courteous to the non-chicken majority so the rest of the city chicken people don't get punished through politics and zoning.
I submitted pictures of this coop to someone who was working on a coops book a while ago and they included a picture of it in "Chicken Coops, 45 Building Plans for Housing Your Flock." By Judy Pangman
Sources for my chicken knowledge:
"Building Chicken Coops" Gail Damerow
The City Chicken, http://www.thecitychicken.com/
Backyard Chickens Forum, http://www.backyardchickens.com/f/
FeatherSite - The Poultry Page, http://www.feathersite.com/Poultry/BRKPoultryPage.html
I recently posted another coop, a chicken outhouse with a beer can roof at diylife.com