HI there, this is Dr. Elaine
If you have had a documented case of Mareks within your young flock, the others have already been exposed. That does not mean infected, but it is highly contagious, so I would expect others to become ill quickly.
That said, you can vaccinate them, it won't hurt them, but may not be in time to protect them, either.
Once birds have the paralysis, they almost uniformly die, as this is from actual tumors in the nervous system which to not resolve on their own.
Vaccination does NOT prevent infection, mind you, it simply prevents tumor formation--birds can still carry the virus, but will shed it much less and be much less infective to others.
Should I vaccinate all the chickens in my yard then? there are 4 more from the same brood, and there are other older birds that have not shown Marek's sxs?
Where can I buy the Marek vaccine? I live in the state of Washington.
Thanks alot. Appreciate your fast response.
The older birds rarely contract the disease, although may already be carriers. You can find the vaccine at some feedstores, but you may have to call around.
Ag extension offices can guide you, but there is often the problem of buying the vaccine in 100s of doses.
In all practicality, if these were my birds I would concentrate on sterilizing the brooder, and only introduce birds that are vaccinated when you add to the flock, as all have already been exposed--it works that fast, especially in a small flock where everyone is together. Vaccinating now is not going to be effective.
McMurrays hatchery will ship you vaccine to use in new babies--or they'll do it for you if you order birds. I have often ordered my non-4H birds from them and I've been very happy.