I have a teenage hen that I noticed was not perching one night and sitting in nesting box. When I tried to get her up she was not standing up and kept falling over. I immediately separated her from the rest of the flock. She eats and drinks water and stool has been solid and normal. She can move around but still seems unbalanced. I have been giving her electrolytes and vitamins e, b, and selenium. She is alert but this morning she only keeps one eye open. I looked at other posts and can't seem to get what she has. Any thoughts?