My 4 month old Barred Rock hen has started getting dizzy and even passing out now and then. She also breathes heavy after coming to. Her eyes aren't running. She's eating and drinking fine. Her crop is fine. She will fall asleep when I hold her and she shivers a little. I've brought her inside, but she hasn't pooped yet, so I can't say what that looks like. Does this ring any bells for anyone?