Well, I'm not a vet or anything, but I once had some birds get crusty eyes that were sealed shut. Being a nurse, I treated the symptoms and cleaned the eyes with a warm wet towel that I kept rinsing and rewarming and followed by applying triple antibiotic ointment. (Note.....I am real quick to use warm salt water for any wound on any creature. I find it heals faster)
It later became apparent that the problem was imbedded in the brooder I had them in, because the next 'crop' had the same problem, so before using the brooder on any new baby birds, I cleaned it on high pressure and applied large amounts of Tide and Clorox to set there a while and then rinsed again at high pressure and kept it vacant for a long time. I had only one long lasting problem. One of my hens did go completely blind in one eye, but other than that I was lucky. Whatever the problem is with your bird, good luck and I hope it doesn't spread to the rest of them. Maybe consider treating them with an oral antibiotic you can put in their water, just as a precaution.
I am a firm believer in vaccinations.....I hope this isn't the first sign of something worst than just a sick eye.
