Ema, from what I have learned is that there are two main reasons for this to happen.
Although she has 2 ovaries, only one of them is working. When this ovary, for example, gets infected (inflammation) hormone production can get confused. The other ovary might start working after some time, but the balance of hormones produced by that ovary is different, so change of behavior (or male dominant features and behavior) can occur.
Since she is still laying, I hope there is no infection.
If an infection on her ovary is the cause of this, then the behavior might be least of your problems.
Maybe a good vet can help you out, finding out if there is an infection?
The other reason could be that there is need for a male in the group.