My healthy, laying hen got sick about a week ago. She is really unbalanced, and when she looks very upright. Whenever she stands still, it looks like she's sitting like a human, with her body vertical. She has to flap her wings to move sometimes. I put her in a separate coop a few days ago, with some food and her own water, but she doesn't seem to be getting any better. She's becoming less upright, and she eats and drinks relatively normally, but her coat is dull and she looks very sick. I don't know what to do for her. Could anyone help me? Do you know if this is a kind of disease?