I realize this is a very old thread but I'm currently having a hen act in this exact manner, and am incredibly fearful as to what is happening. Have you gained any insight into what may have been wrong with her, and what happened to her? Please share if you can.She now is having fits and spasms - I know there is no hope for her but does anyone know what this could have been, as i have another 5 hens who seem poorly today. I cannot understand how she seemed fit healthy and happy at 12.30 pm Friday, in 5 hours she became blind, 24 hours later she was still getting around, was alert and eating and now less than 24 hours later she's having some sort of brain seizure. Has anyone experienced this?