Sour croup? Feel her crop, the bit below her throught, where the corn is stored before digesting. If that feel very hard, or even squishy, tip her over gently, and gently press on the croup. If its sour croup, foul green or brown liquid will come out of her mouth. Or syringe some veg oil into her mouth, and that should have the same effect. I have had this happen to mine, and lots of grass comes up. It may help if thats what it is.