An egg is excellent and helps rule some stuff out!
The crop condition still desperately needs to be addressed hopefully before she aspirates any fluid into her lungs.. it's a dangerous condition. Did you read that link?
:fl
Sounds like a possible blocked or sour crop.. though the problem may be lower down.. see if this article helps at all..
https://www.backyardchickens.com/articles/how-to-treat-sour-crop-and-impacted-crop-and-how-to-know-which-one-youre-dealing-with.73607/
Is she pooping?