Please Help!!

I am not sure what is going on with my hen, she is sleeping a lot!! When she sleeping she kind of turns her head backwards towards her tail or to the side by her wing and slowly rocks it back and forth, not usual for her. She is about 2 1/2 years old. She appears to have gone blind in one eye also. She seems so be eating and drinking normally, i have her separated from the other chickens and I have not noticed a lot of poop. I appreciate any help!!!