My 41/2 year old light brahma hen's left eye is sort of fluttering open and shut. Most of the time she will keep is shut. Then, she will open it up, and then close it. That has happened since 4:30 pm or so, because I didn't see them until I came home. My sister let them out to roam this morning, and said she were fine. Her right eye is clear and doesn't appear to have any problems. She's been acting normally, it's just her left eye. She is also eating/drinking and responding. Her physical appearance is also ok. Should I be aware of something? Please try to answer as I am new here and would love if you could help. Thanks.