I am new to chickens and when I first hatched my girls in August I knew nothing about vaccinations. As I have been reading more and more I think I am leaning toward vaccinating going forward. Since I have a hatch due Friday I went ahead and ordered the Marek's vaccine and plan to vaccinate the new chicks. I also have older unvaccinated pullets that I am considering vaccinating at the same time as well but I have a few questions I hope you all can help me with. Marek's Vaccine I live in a very big city and the older pullets are in my backyard flock. As far as I know there are no other chickens in the neighborhood. Do you think my 5month old girls have already been exposed to Marek's? Would it be worthwhile or beneficial to vaccinate them now? Newcastle's Also, I went ahead and purchased the Newcastle "vaccine" (that can be added to the water or administered into the nostril of the chickens) when I purchased the Marek's vaccine but am not convinced I want to actually give it yet. In my research I've learned that the Marek's strain from the vaccine is not "shed" from a vaccinated chicken there is no possibility it could infect an unvaccinated chicken. I cant find this information about the Newcastle vaccine though. Does anyone know if the virus is shed by vaccinated chickens and could pass on to unvaccinated chickens? Is this a vaccine that is suitable for a backyard flock? And, if I do vaccinate with either of these vaccines, do I need to discard their eggs? If so, for how long? Are there any other vaccines I should consider? My chickens are my pets first and I want to make sure I do whatever is in their best interest for their health but I want to make sure I am making educated decisions. Thanks all for your help!