Have you checked her butt?
The vent of a laying hen looks different from a non-laying hen, and the change shows up a little before they start laying. (Small puckered vent on chick, rooster, non-laying hen. Wider, stretchy-looking, moister vent on laying hen or one that's almost ready to lay.)
You can also feel the tips of the pubic bones, on each side of the vent but a bit below it. They get lower and farther apart as she gets ready to lay, and close up again if she quits laying (molting or broody.)
There's also an article about it:
https://www.backyardchickens.com/articles/who-is-laying-and-who-is-not-butt-check.73309/
Based on your picture, I would think she is close to laying, or she might already be laying and hiding the eggs somewhere. But chickens are good at keeping us guessing, so she could also keep you waiting for a while longer.