Here's the directions I read for sour crop-
Separate hen, 24 hours with no food, only water with 1/4 teaspoon of acidified copper sulfate (comes in powder form usually at feed store) in a gallon in plastic waterer only. If you can't find that, use two tablespoons of organic, unfiltered apple cider vinegar on the plastic gallon waterer changed daily. Day two add only plain yogurt. Day three add plain scrambled egg to the yogurt. Each day massage the crop several times a day pushing toward the back of the crop, not upward, day three maybe some soupy oatmeal added to eggs & yogurt but no grains. Don't make throw- up that can kill them. Best of luck.
Separate hen, 24 hours with no food, only water with 1/4 teaspoon of acidified copper sulfate (comes in powder form usually at feed store) in a gallon in plastic waterer only. If you can't find that, use two tablespoons of organic, unfiltered apple cider vinegar on the plastic gallon waterer changed daily. Day two add only plain yogurt. Day three add plain scrambled egg to the yogurt. Each day massage the crop several times a day pushing toward the back of the crop, not upward, day three maybe some soupy oatmeal added to eggs & yogurt but no grains. Don't make throw- up that can kill them. Best of luck.