You know, I would have a talk with the state vet or pathologist that did your necropsy. Cryptosporidium is pretty dangerous to other chickens. If that one has it as well, I am not certain that I would mix them. The eimeria tenella is one of the worst strains of coccidia, and if those chickens...
Sorry for your loss. Shipping a 4 week old chick to me would be very stressful. They are used to eating and drinking all day long, and running around. Spending 2 days in shipping could cause chilling especially in Feb., dehydration, and stress. Day old chicks can tolerate going without food and...