Sour crop can be the side effect of impaction.
http://sites.google.com/site/moodysbantams/poultry-health-1/crop-impactionKeep her separate, take away her feed and only give her ACV water (1-2 tablespoons to a gallon) for a day, then start giving her yogurt and scrambled eggs. Nothing she has to grind up though, only soft stuff for the next day or two. You can also add water to moisten her feed but avoid any grains.
If she doesn’t seem to be improving or is getting worse, I would try giving her an anti-fungal like nystatin (used to treat yeast infections and thrush) asap.
Also continue doing crop massage. But please, please be careful if you decide to induce vomiting again. I honestly would not. I learned the hard way how very easy it is to aspirate a chicken.
If nothing seems to be working or you don’t have any of the above on hand and you’re desperate, here are a few untried “last resort methods” I’ve only read about:
Give 6-10 cc of flat coca cola via a syringe. This apparently will help dissolve the food particles impacting the bird. Then give 5 cc of mineral oil to help unplug and yogurt to help restore good gut bacteria.
Copper sulfate mixed in water. Google for exact instructions. Just be very careful to use as directed. It is very toxic stuff.
Crop surgery…*warning: link has graphic pictures*
http://www.backyardchickens.com/forum/viewtopic.php?id=229796I hope something here helps and your girl is feeling better soon.