I bought 2 6 week old amerucanas about a month ago. A couple weeks ago, one of them was acting lethargic and sitting with her eyes closed. I separated her from the rest of the chickens and treated her with tylan powder in her water for 5 days. Now she has her eyes open but she acts like she can't see. When I wave my hand in front of her, she doesn't react and when she walks, she runs into things. My husband said she always seemed a bit "off" ever since we got her and he thinks there has been something wrong with her sight since we got her. Has anyone seen this? Does the eye sight return?