Was it actually poop that ran out of her mouth or was it a foul/sour/yeasty liquid - she more than likely has sour crop.Her crop is empty. We did an exam but couldn't feel an egg. When we turned her upside down poop ran out of her mouth. We did a water enima and she seemed to liven back up fairly quickly. She's drinking but not really eating at this point. She's much more alert but still weak and slow.
What is a water enema? Can you tell us how you did this?
I recommend that you read the article I have linked in it's entirety, it give good information on how to treat difficult sour crop and crop issues:
https://www.backyardchickens.com/a/impacted-slow-and-sour-crops-prevention-and-treatments