This is most likely a fungal/bacterial infection. You should get Terramycin ointment, I believe you can get it from TSC, and apply it to the eye multiple times a day.
Flushing the eye with a saline solution to clean up anything that could be in there would be a good idea as well.
Could she have been pecked in the eye? You can flush the eye with saline or eye wash, and apply either Terramycin or plain Neosporin ointment into her eye twice a day. But it would be good to remove that white gunk which may be infection or scar tissue. If it were me and she was important, I would try to see a vet or farm vet soon. Hopefully, she won’t lose her eyesight, but that is a possibility. Please let us know what happens.