Help! My laying hens have had a recent drop in egg production and i can't figure out why. The only strange symptom that some of them have is the loss of feathers around their combs. Some of them have loss of feathers at their necks but that may be the rooster since these birds also have bare spots on thier backs. One hen is more sickly than the others, she is very lazy but when i get close to her she perks up and runs away. She keeps "closing" her inner eyelid while she is sitting. I picked her up and I can't see any mites but did notice that she has a poopy butt- not blocked, but the feathers are all streaked with dried poop. They have no respiratory symptoms at all. Ideas?