Hi all- I've raised chickens for a couple of years now, and my flock keeps expanding, to the point where I now have 17 hens -- and they need a new coop! Their current coop is too small, with 5 nesting boxes and two roosts, and we would like to expand to fit everyone more comfortably. We'd like the coop to be as small as possible, to keep building costs down and to maximize the yard space. Our hens only use the coop for roosting and laying eggs. The coop door is on a timer, and from dawn to dusk they spend their time in their large 20x30' yard. Our northern-california climate is really mild; in the occasional rain-storm, they have several areas in the yard to stay dry. Their food and water are kept outside of their coop. Given those factors, I have two questions: 1) Will an 8x4' coop be big enough for my 17 birds? We will have exterior nesting boxes adding another 16 sq ft. That brings the total square footage to 48 sq ft. -- around 2.8 sq ft/hen. I know this is smaller than recommended, but they still have more than 30 sf ft/hen outside to roam in. and, more philosophically... 2) When calculating "square footage", is it fair to add "vertical" space, such as their roosting perches? I don't want to "cheat" my calculations, but it seems like vertical space should count for something. The enclosed area of our coop will be about 4' tall with room for two roosting perches. Looking forward to hearing your responses. Thanks in advance!