Do you have photos of her?
A video of how she moves may be helpful. Upload video to YouTube and provide a link.
What do you feed, including treats?
Was she vaccinated for Marek's?
Is your Pullet laying eggs yet?
I would start by examining her for any injury/bruising or swelling that may be causing difficulties walking. Do you have a rooster/cockerel that may have injured her?
Could your pullet have jumped from a high roost and injured herself?
I'd provide the pullet with 1/4 tablet B-Complex daily. She may benefit from extra protein if she's on layer feed, give her a bit of egg, fish or meat.
Hard to know what's going on with her. A pullet that age could be showing signs of Marek's disease. If she's not come into lay, then she may be having some reproductive difficulties.
If you happen to lose her and want to find out what was ailing her, then sending the body to your
state lab would give you information.