Vaccinating older birds

[Trevorusn]

After receiving lab results confirming, as much as a lab possibly can it seems, Mareks in my flock, I have decided to vaccinate my flock ranging in age from almost a year to 5 years old, 30 birds in all. Where are the best sources to get the vaccine from, and where would the best injection site be?

 

[Eggcessive]

Sorry for your diagnosis. It is too late to vaccinate. They have already been exposed to the feather dander, and it can remain in your environment for months to years. I would consider all birds to be carriers, and I would close the flock to birds going out or coming in until every bird is gone. But you may find that some birds may die while others may seem immune. Here is a good article that contains a lot of info:
https://www.backyardchickens.com/articles/the-great-big-giant-mareks-disease-faq.66077/

 

[Trevorusn]

I have read several sources saying at the very least it won't harm them, and may indeed help. It seems there is no clear or concise opinion on this, except that it wouldn't hurt to attempt it.

 

[Aplatn]

I’m seeking this information as well. I had one hen die of Marek’s and while vaccination in older birds is not as effective and and immunity isn’t guaranteed, it could possibly lower the risk from Marek’s.

 

[Photolady]

I also have a mareks positive flock. I have new chicks ranging from 1-10 weeks but they have not been exposed outside yet. I am doing this intentionally to keep them from exposure to the flock as much as possible and I have the vaccine and intend to vaccinate all the birds that have not yet been exposed, even the older chicks. Hoping for the best.

The biggest thing I am looking for is information on vaccinating all of them properly. Once they get the vaccine, they will get one more week in isolation, then I will start putting them outside during the days.