I have a sick hen. She has seemed sick for a while, but it is pretty unclear what is wrong with her. She is energetic, eats a lot, has a full crop, is able to pass waste and still lays eggs. However, she is losing feathers and not growing them back, and she is wasting away, getting skinner and skinner by the day. She doesn't have mucus around her eyes or nose. She doesn't sneeze or seem to wheeze. None of my other birds are sick. The vet tested her for parasites, and she doesn't have any. I have no idea what is wrong with her, but she is my favorite hen, and I will be sad if she dies. The vet suggested a sour or impacted crop (though she doesn't seem to have any symptoms associated with that), and a fungal infection (Aspergillus). A fungal infection seems likely, though I can't find any details on-line about symptoms or treatment. Can anyone advise?