I had a 4 month old chicken pass away the night before last and a 5 mo. old last night. They both seemed healthy before. Both were eating and drinking no raspatory issues. The only thing I have noticed in just one of them was that she seemed more tired than usual. they were both eating and drinking. I have 8 more in the coop. Three are 1.5 yrs and the rest are 5 months old as well. I have cleaned out the coop today disinfected everything replaced the pine chip bedding and the chicken starter grow that is medicated and they have all been on since we got them. They are pets to us and we are really attached to each one and spend alot of time with them. We had seen some mites but have those under control. I have noticed a couple of them have had runny stool that may have some specs of blood in it (Not positive though) and I saw a couple with yellow runny foamy looking stool. I have put Corid in the drinking water yesterday. Im devested and at a loss what could be going on. No pale combs or swelling of the face either.