My first coop has 25sqft of floor space (plus roosting space up high) not including the 6 nesting boxes on the side, and the second coop has 15sqft of floor space, also not including the nesting box, and areas to roost as well. There is plenty of run space so I am not worried there. I have 14 hens and 1 rooster currently. 9 are smaller breeds (EE/cream legbar mixes) and 5 are larger (RIR). The rooster is pretty large as well. I was considering adding 3-4 more hens to the flock, but not if it will mean I am overcrowding. It is tempting because one of my cream legbar mixes has been hellbent on hatching eggs and I am almost starting to feel bad taking eggs from her every day. My main concern is winter. I am in WV, and depending on the year, we can get 4 months of real nasty winter weather. I admittedly have always been a little confused about how much space they need in the coop, and how much time they spend in the coop during winter since this is my first year with chickens.