Last year we got our first chicks, and had them vaccinated against Marek's and coccidiosis. We will be picking up our current year chicks from the hatchery next week. I read (somewhere!) that my prior, vaccinated chickens are now carriers for Marek's. Therefore I am having all new chicks vaccinated. Is this correct? I am not planning to vaccinate the new ones against cocci since apparently it is in the ground anyway, and I do have some sulfa to treat them with if needed. Does this all sound like the right thing to do?