When my chickens got some bad feed i gave them a molasses flush....I don't remember the dosage but it did the trick and they bounced back fairly quick....I haven't had to deal with an impacted crop though.....but this link might help you diagnose and treat her...http://www.greenmuze.com/blogs/green-muzings/2208-chicken-impacted-crop-or-sour-crop.html....good luck