I have an Easter Egger who is about 4 years old who is suddenly going blind. Both of her pupils have constricted and are not perfect circles anymore. The don't react to a flashlight and don't change size with light.
Like Marek's, her pupils are tiny and not perfectly round anymore (one is a little cat like, and the other a little amoeba like). Unlike Marek's, the iris color is still her original orange color and not gray/blue like Marek's. I've seen many pictures of Marek's eyes with gray iris.
Is it possible to have Marek's and still have the original orange iris color?
Other info: One of about 40 chickens, free range with feed always available. No other chickens showing any symptoms. This Easter Egger is now staying inside in a dog kennel, doesn't offer to come out of the kennel despite the door being open. She is eating (can see a tiny bit and can see food dish) and is drinking. Enthusiastic about treats. Poop looks normal. Isn't walking much, but suspect it's because of being nearly completely blind. Just coming off of a hard molt, so she hasn't laid an egg in about three months. Eyelids look normal. No limp, no sores, no wounds, no snotty nose or gurgling or anything other than sudden pupil constriction.
The coop is a bit overcrowded, and she normally sleeps on the top rung. My daughter "forgot" to clean the coop, so it was very poopy. I'm wondering if it isn't related to too much ammonia, but she doesn't have any other symptom of ammonia poisoning.
TL;DR: Does Ocular Marek's have to have a gray Iris to be Ocular Marek's, or should I be looking at something else?