You can get Monistat or miconazole cream or suppositories at Walmart, and use it orally for yeast in the crop. If you read the article in post 3, it gives a lot of info. Some also recommend acidified copper sulfate 1/4 tsp per gallon in the water for a few days for sour crop. Many suppliers sell...
You can get some probiotics at many feed stores, such as Probios or the generic. Plain Greek unsweetened yogurt has some. Is there a bad odor from her beak? And you are certain that her crop is completely emptying overnight? Have you checked a few others crops to make sure it isn’t lower? The...