On one particularly day, I had a perfectly normal chicken begin to show signs of blindness in one eye (would only look through one eye and would keep the 'blind eye closed'). in a matter of 3 days she had a cloud over her pupil and I'm unsure as to what it is. It looks like a cloud on the outside of the eye (when you look sideways, the cloud does not enter the eye). She became a little lathargic at the same time. she no longer closes the eye, she just doesn't use it. I have also attached a photo. Please help me identify the issue.