I believe you when you say it said 6. I have been on this website for a long time, and anymore, if someone says 'Oh, I have a flock of six, and they have just got started- my first questions "is it a pre-fab coop?"
They really, really should not state that.
As for numbers... thing is, some chickens (it has breed tendencies, but is really dependent on the chickens you have) can take a little overcrowding, and some cannot.
I do understand this is not what your heart wants to hear... but you do have 5 that are working out. Maybe sell the BO, and the other one. This is not a guarantee that 5 will work in there all winter, but it is so far.
If you decide to keep the BO, then I am thinking you will have to go to 4. BO tend to be larger birds, and less dominant (tendencies, not carved in stone) if you keep her, I would drop to 4 birds.
Mrs K
