Oh, boy, do we have that problem all the time! Get some eyewash from the drugstore; the kind that has mainly boric acid in it but isn't contactl lens stuff. Drop some on the chick's eye, then apply terramycin eye gel twice a day. We also give them terramycin soluble powder in the water 4 tsp per gallon, and used that strength for our chicks too when they were first sick with ILT. We hold the chicken for a few minutes after applying the eye gel, so they dont just wipe if off; but it seems to feel good. If you do it right before they go to roost at night, they wont wipe it off. Three to four days max should bring them back to normal. If not, there'r stronger eye drops available; we get them through our vet supplier, but I can't remember offhand what they're called; they work well for more advanced cases. Eye problems are caused by a lot of things; our most recent episode was caused by old straw in their bedding. . We got rid of the straw, and applied the meds; cleared up in two days.
