We noticed this yesterday after it rained. It looks like her eye is white and bulging.. she's not doing much some kind of upper respiratory infection...
It is hard to say what it is from the picture. Can you get another one in light? What symptoms does she have—any sneeze or cough, wheezing, gasping, nasal drainage? Can you clean the eye with saline eye wash, and use an antibiotic ointment in the eye twice a day? Does the eye seem intact, or have bubbles or pus in it?
Welcome.
How long have you had her and any nw chickens brought in recently?
Can you get a closer picture of her eye?
I am guessing you are seeing pus, which will need to come out and then you will probably need to start antibiotics.