This evening my wife let our chickens out of the run for some exercise and noticed one of the hens did not come out. She went into the coop and brought her outside. The hen didn't move. Upon inspection my wife noticed the hen did not react to movement and had no fear of my wife's hand being near her face. We contained her and gave her some yogurt. She gobbled down the yogurt, but when we took the food away she continued to peck at the spot. The hen appears to be blind. this hen is a Golden Comet about two and half years old. Other than being blind and hungry, she appears to be fine. We will keep her contained tonight and check her again tomorrow. Does anyone know what might have caused her to go blind? If so, is there anything we can do for her? Thank you in advance, Goshen.