Only thing is she is Broody. If there are any eggs in the nest box then she is sitting on them "broody" and waiting on them to hatch. This will go away when the eggs hatch or in about a month if they haven't take them out yourself and she will soon go back to normal.
If she is the only bird in the coop and there is no rooster then there is no way the eggs will ever hatch, they haven't been fertilized. If this is the case in about a week go ahead and remove the eggs before they rot and start smelling and she will get back to normal soon.
If there aren't any eggs she will figure it out on her own in a week or so and resume normal activities.