Does she lay eggs? Have you noticed a bad or sour odor from her beak? I would stop any whole grains or seeds, and feed her a small amount of chicken feed plus a lot of water mixed in. A spoonful of plain yogurt daily is okay. Watery egg is okay too. If you can get miconazole cream or...
It sounds like her crop is slow or possibly sour. That can happen from an impacted crop or sometimes they can have a primary problem causing the crop to not empty normally. That could be worms, a reproductive disorder such as salpingitis, cancer, or infection, or even ascites (water belly.) Here...