I have been looking and asking around about this issue and nobody seems to know anything. I didn't want to take my chickens into a vet but just might. I had one chicken that looked like it was getting cataracts. She can still see somewhat and eat. There are no other symptoms. Other chickens are getting it, different breeds. I tried antibiotics in the eye, looked for eye worms and saw none (we also don't have cockroaches that typically carry the eye worm). The cloudiness is in the pupil, so doesn't fit the description of Mareks. It starts little and eventually fills up the whole pupil. I was feeding them extra things in their feed, sunflower seeds, probiotics, kelp, oats, diatomacious earth, and omega 3. I started feeding oyster because their eggs were getting a little thinner. I stopped that and more chickens are still getting it. My chickens were hatched last year. Anyone have thoughts?! I am thinking of deworming.