My coop has room for about 25 birds. I have 7 that live outside right now and 11 more in the brooder (and more in the incubator). Some of them are banties though. And I have another "coop" sitting outside that I can fix up if I need to.
I have a big barn. Each room is 20 x 25 more or less. I have 5 rooms and a stall area. The barn was built in 1915 and was a commercial laying house. It looks ugly and unpainted but we'll get around to fixing it up one day. My house is more important.
I have 53 currently. 49 chickens and 4 peas. (And several pigeons and doves also.) I have more then I have cage space for. I let my most crowded chickens out for most of the day though. I am building another covered cage now for the bantam RIRs and I plan on letting the Seramas, sebrights and Bantam Phoenix out to be free range permently after I get a shock collar for my dogs.
I have the room, just not the protection of cages for them to be nicely spread out at night and in the morning before I let them out.
I lost track, but somewhere around 100. I have way more room, but there is a very large man glaring at me in the way of filling the other acre with chickens.
(love you dear!
But currently we have an 8x8' layer coop with surrounding pen, a 12x24' breeder pen housing 5 breeds of chickens, chukar partridge, and 3 breeds of quail. A turkey pen, with Thanksgiving for the next three years in it, 2 duck pens, and 5 rabbit hutches. I am officially out of room until a) I sell some birds (soon!) or b) we eat some birds or c) Spring.