We ordered our day-old chicks from Murray McMurray's and they were supposed to be vaccinated for both coccidiosis and Mareks.are you talking about the mareks vaccine or coccidosis or both?
One of our Phoenixes did get vet-confirmed coccidiosis when she was around five months old, although I understand that vaccines aren't 100% effective. I initially thought she had Mareks since some of the symptoms are similar and was going to euthanize her, but treated the whole flock with Corid and she recovered.