Has she been laying recently? I would put her back in the coop tonight, remove any food or water until you check her crop again in the morning to see if it has emptied. Smell her breath as you feel the crop for a bad or sour odor. Then feed and water everyone. What do her droppings look like? If you need to keep her inside tonight that would be fine, and then you could look at her droppings from the night.
I have hens who have been sick who take to the nest boxes. They also may hide there if they are being bullied. Is her tail position up or down? Does she have an enlarged lower belly between her legs? How old is she? Can you look her skin over for any lice or mites?
If her crop is full and puffy in the morning, here is a good article to read about crop problems.
https://www.backyardchickens.com/ar...w-to-know-which-one-youre-dealing-with.73607/