I moved into a house in my city that used to have chickens. It already has a coop (about 4 feet by 4 feet, not counting four nest boxes, with a sloped roof ranging from about 2.5 feet high at the back to over 4 feet at the front) and uncovered run (long side is about 30 feet and short side ranges from 3 to 10 feet). Their food and water are kept outside the coop. The hens are really only in there to sleep, and there's an automatic door so they can get up right at dawn. Ideally I'd like 6 hens ("retiring" 2-3 each year so I have a variety of ages). Is the coop big enough for six? I know the standard recommendation is 4 sqft / bird as a minimum. If it isn't enough space, is there a way to add more coop space without having to start from scratch? I don't know if the birds would take well to a small second coop, but at the same time I'm not sure I can expand the existing coop without basically tearing it down.