Hoping someone can help? I had a small flock of 7 but have lost two in the last week. Symptoms are shaking, green poo, twisting neck. They have shown no symptoms one day, but really poorly the next and then not made it through the day. :-( from what I have read it could be mareks? I have three older hens that came from a large farm and I have had about two years. I am pretty certain they have had vaccinations but I got the other four locally. They are about 6 months old. Is there anything I can do to prevent the others catching it?