Hi, I have a hen that quite suddenly started limping. She was fine this morning, and now one of her legs is limp. she is still alert, I haven't separated her from the rest of the flock because she freaks out when she is, and I didn't want to stress her more. Also, her eyes are a bright blue. Do you think it's mareks? I had a hen die of it earlier last year. I hope it's not! I examined her leg, and can't find anything wrong with it. Please help!