If you haven't already, I would try to see if there is something in the eye, maybe in the corners, being careful to avoid doing anything that may embed the irritant if there is something there. If you do see anything embedded, I would either take it out myself with a *very * steady hand and tweezers or better yet, take it to a vet. Or the chick could have had its eye scratched, by itself or another chick. If you think there's something in it, maybe try rinsing the eye with saline (not straight water) to encourage washing out of the irritating substance or foreign body. If the chick's scratching seems to create more irritation, you may need to bandage the eye to prevent further scratching and damage. Hopefully it will clear up on its own and not become infected, whereapon I may give it Terramycin as a last resort, if I know if no foreign body is actually in the eye. Hope this is helpful. I'm not a vet or an opthamologist, but this is how I would try to remedy it.
