Is the white part of her poop on the yellowish side, or is that the lighting? I would check some other crops of your hens just to get familiar with what they feel like. They should be full by evening when they go to roost, and by morning be mostly empty and flat. If they are not empty, then they may have a crop disorder. Chilled coconut oil cut into small pieces can be offered and then the crop can be massages. She could have a reproductive disorder or a crop problem. Offer fluids with some electrolytes, and a little wet chicken feed plus a few bits of cooked egg. Let us know how the crop feels in the morning. Here is a good article to read about crop disorders:
https://www.backyardchickens.com/ar...w-to-know-which-one-youre-dealing-with.73607/
https://www.backyardchickens.com/ar...w-to-know-which-one-youre-dealing-with.73607/