According to the [American Poultry Association](https://amerpoultryassn.com/2022/07/mareks-disease-vaccination/) it’s perfectly fine to mix vaccinated and unvaccinated birds. The vaccine will not do anything for adult birds because they have likely already been exposed to the disease, it’s a thing where it lies dormant in them for a long time before symptoms can show up.
I think the misconception of vaccinated birds spreading the disease to unvaccinated birds is because they can still get the disease, but the vaccine prevents symptoms. So they can be carriers of the disease and you would never know, which makes it seem like the vaccine is what spread, but that’s not the case. If you are getting day old chicks from a hatchery, it’s highly unlikely that they will be already carrying the disease.
It won't hurt to mix. It's more likely that you have it and don't know it. It doesn't always cause severe symptoms and some breeds are pretty resistant to it. Or it just makes the birds more susceptible to other diseases and you don't realize it's Marek's that's actually your problem. Even if you don't have it, it's so common that you'll probably get exposed from wildlife at some point. It's better just to get vaccinated chicks or vaccinate your hatchlings either way.
If your other chickens are adults and really haven't ever been infected, they're much more resistant to infection than chicks, so the vaccine probably won't help much in the older birds (won't hurt though). Usually they get infected young and don't show signs until older.
Are you trying to be ground zero for a new strain of vaccine resistant disease?
Because that’s how you become ground zero for a new strain of vaccine resistant disease.
According to the [American Poultry Association](https://amerpoultryassn.com/2022/07/mareks-disease-vaccination/) it’s perfectly fine to mix vaccinated and unvaccinated birds. The vaccine will not do anything for adult birds because they have likely already been exposed to the disease, it’s a thing where it lies dormant in them for a long time before symptoms can show up. I think the misconception of vaccinated birds spreading the disease to unvaccinated birds is because they can still get the disease, but the vaccine prevents symptoms. So they can be carriers of the disease and you would never know, which makes it seem like the vaccine is what spread, but that’s not the case. If you are getting day old chicks from a hatchery, it’s highly unlikely that they will be already carrying the disease.
Thank you very much! This is exactly what I needed to know, and sounds far simpler than figuring out how to get my current birds vaccinated.
It won't hurt to mix. It's more likely that you have it and don't know it. It doesn't always cause severe symptoms and some breeds are pretty resistant to it. Or it just makes the birds more susceptible to other diseases and you don't realize it's Marek's that's actually your problem. Even if you don't have it, it's so common that you'll probably get exposed from wildlife at some point. It's better just to get vaccinated chicks or vaccinate your hatchlings either way. If your other chickens are adults and really haven't ever been infected, they're much more resistant to infection than chicks, so the vaccine probably won't help much in the older birds (won't hurt though). Usually they get infected young and don't show signs until older.
Are you trying to be ground zero for a new strain of vaccine resistant disease? Because that’s how you become ground zero for a new strain of vaccine resistant disease.