It could be she's struggling with a stuck egg or is internally laying. I would give a calcium supplement in case she has a stubborn egg hung up. It will stimulate contractions to help move the obstruction. This is what I recommend. One tablet immediately directly into her beak. Don't put it off...
Read this to bring you up to speed on crop issues and treatment for each type. https://www.backyardchickens.com/articles/how-to-treat-sour-crop-and-impacted-crop-and-how-to-know-which-one-youre-dealing-with.73607/
Now, you are going to have to pretend we here in internet land don't know a...