Sick Chicken

We love our hens, they are family. One of them is sick. We have had her to the vet twice and she is no better. Started with one ear draining fluid and in corners of her mouth and now both eats, nose and corners of mouth are draining some kind of mucus. She is constantly opening her mouth up wide and shaking her head. The vet prescribed ear drops and an antibiotic, but it hasn't helped. The vet first said she had an ear infection and the next time we took her they said that she may have a mite and she was treated for it. Don't want to keep running up bills at vet if she is really sick with something that can't be treated. Anyone got any advice for me please??