My hen had an impacted crop that had soured. She had lost a lot of weight. I brought her in the house and kept her in a dog crate we use as our chicken hospital. I was able to clear the crop. She was getting back to normal, eating, drinking and regaining strength. Then suddenly she got extremely lethargic...barley opened eyes w/attempts to rouse. The next day seemed mostly back to normal except now she has very limited vision...too little to function in coop & run. There are no physical signs of a problem. Her pupils do react to light. Wondering what could have caused it? Malnutrition from impacted crop (she lost a lot of weight)? Yeast in sour crop? Is there any likelihood of her vision recovering? Is there anything I can do to improve her vision?