It's hot here - gets up to 115 in the summer. In the winter, it rarely gets down to 32 degrees, so we built a 3 sided coop instead of a fully enclosed one. Our coop is 5' x 7 1/2'. We used a 13' x 7 1/2' dog run found on craigslist for the first chicken run. The original coop/run space is 135 sf, but we have since added a 6' x 10' run to the side. This second run opens up to the first one for an extra 60 sf of run space. Our 20 hens/pullets seem to like their home, but especially love their freerange time, which they get daily from about 3 p.m.- till dark.
After adding nestboxes and roosts.
My husband built our nestboxes from old cabinets and included extra storage for me. The roof is slanted to keep the chickens off. The left side holds a 50 lb. bag of feed, while the right side has some extra storage above the nestboxes.
They like their nestboxes and aren't too particular - the hens are just as happy with cat litter boxes too:
We ended up with more chickens and decided to expand their area. We added a second chainlink dog run (6' x 10') that connects to the first run for another 60 sf of run area for the 23 pullets/hens we now have (makes an L shaped run). This second run is covered by metal corrugated panels and is secure against predators since some of our younger pullets sleep there. I can also close it off for a second pen (for raising chicks, etc) if needed.
Just this week, we added even more daytime run area by using some extra horse panels we already had for an even larger run. This last run connects to the first one - it is not secure against nighttime predators like the first two are, so the chickens don't have access to it until about 10:30 a.m. or so. It gives the chickens alot more space to scratch around in. I still let them out for a few hours every day for free-range time in our backyard.