This past week i was out of town and left my healthy chickens behind. I had a neighbor watching them that had done it many times before. When i came back I found zombie like chickens. They had very low activity which is VERY odd.One was walking around with its eyes closed. and protecting the food even though she wasn't eating it. A few have a yellow substance coming out of their nose and most of them are lethargic. Only about 4 of them are up to par but the others aren't looking too good. Their egg production has slowed down a lot. We just dusted them about a week ago. They have also started eating their eggs. Please help ASAP!!!