Does she kind of look like she is walking like a penguin?
It might be internal laying.
Go do a search in the box at the top of this thread, and type in 'internal laying'.
Speckled hen had a girl she worked on for a while with this.
Oh my goodness! How long has it been since she last laid? Have you examined her to see if you can feel an egg? What does her crop feel like? If she is egg bound there are some things that you can do to help her. Here is an article from the learning center that might help you help her: https://www.backyardchickens.com/a/egg-binding-symptoms-treatment-and-prevention
I just lost my favorite chicken to egg laying issues two weeks ago so my heart goes out to you.
I have only been a chicken momma for a little over a year but if I can help you I will. I am sure that there are a lot of people on this thread with more experience than I who have successfully dealt with egg binding if that is indeed what is going on.
I'm a little squeamish about feeling for an egg... She is just walking slowly and staring off into space. She's been having issues for a few months with soft shelled or shell-less eggs so idk... It's a chronic issue I wish I could do something about ;(
I will go feel her crop in a few minutes