The picture looks a bit more like a pendulous crop, a condition that comes from overeating and the muscle tone in the crop is lost. It requires some days/weeks of treatment plus a crop bra which holds the crop in so that it doesn’t become overfilled.
@azygous is very good with advice on that, and she wrote the article about crops. She had a picture of a homemade crop bra, and that has to be in the right place to be effective. Stop the ACV since it may fermentation. Give her clean water, some watery egg, plain yogurt, and just a little watery chicken feed. Keeping her on liquids for a day might help. By the way, what are you feeding them? Stop any whole grains or treats right now.