We have owned chickens for at least 8 years now, and have never had such sickness before. Until now. These chickens are only in their 1st winter of life, so about 9 months old. Various breeds of laying hens. The problem is we keep finding them dead, when we find them they have holes in their rears, near or at the vent, and the other chickens are eating them. We care for them twice a day, so its amazing that they can just go down hill so fast and being picked at so agressively in such a short time. It was happening once a week or so, then all asudden daily and and now sometimes 3-4 in a day. Here's the confession, my daughter cares for them, and i KNOW she gives them water and food twice a day, because I watch her do the work while I am doing cows. But I have ignored actually going in there to see how the coop looks. When so many started to die, I thought I better go see. The coop was really dirty. She has not mucked out or even put a fresh layer of straw down in at least a month (I'm so embarrassed to say, but I know for a diagnosis I need to). Other than poop piling up, she gives them fresh water and feed daily, they get scraps and whey and milk, besides their scratch and mash. I really thought we "spoiled' them. But not in cleanliness. Its now been a week, since we have totally gutted the coop and cleaned it, we had a lull in deaths, until yesterday we had 4 more die in one day. We have never had issues like this, other than occasional mysterisous deaths. I dont know anything about chicken diseases. They do look very mangey and motley. Bald butts, red butts, bloody butts. Not all of them are like this, but enough to know that something is seriously wrong. As I observed them last week when we did the coop cleaning, it seemed the were picking things off each other as well...lice? I didnt see bugs, but I didnt look that close either. It just seemed there was lots of picking activity, besides picking at the bloody rears) Well I went out and bought those vitamins to mix in the water, and terrymicin (spelling wrong I know), the antibiotic says do not feed to laying chickens! It didnt say anything about withdrawal, it just said dont ( I see to remember someone else posting something like this but cant recall the thread) We also bought red lights. We totally gutted the coop, chiped away 1 ft of frozen bedding, and spread new down. I do not want to use the Terrymicin until I know about whether or not we can eat the eggs, and if not how long do we have to discard them. Also I want to make sure they really need the meds. But we have had them on the vitamins for a week now, red lights, and a clearer coop. Like I said, it seemed the death rate slowed until yesterday, then 4 more died in one day. The original flock was about in the mid 60's, and I am sure we have lost at least 10-15 in the last month, all due to this cause. Any diagnosis? Treatments?