Flipping Hen ??

Hello! I am in need of some help... I have a hen that has been flipping herself over on her back. Everytime we flip her back she goes"crazy" and flips back over. She kicks her legs up wildly and she twist and turns .. She has no signs of injury , she eats and drinks , and her poop is normal.. I have separated her from the rest. I feel bad for her because I don't know what to do.. Any ideas from anyone what it might be ? Any home remedies ? The vet I called wouldn't let me finish telling her what was going on , she asked if I had money for her to come out and visit , I told her no , just asking for advice and she said my services aren't free , stop wasting my time ..