Sick chickens and brining in new ones

[thejonesgang]

Wwyd?
I have two sick chicks and it could very well be Mareks. We don't know yet. They are at the vet right now . All of my flock hangs out together and free ranges so they have been around everyone. We kept them in isolation for 6 weeks and then released them into the flock.
Is it safe/smart to bring in new chicks when they haven't been vaccinated for it? And can you vaccinate them even if they are several weeks old? I don't want to give a death sentence to new chickens.

 

[Wyandottes7]

No, it would not be safe to bring in new, unvaccinated birds (if it is Marek's Disease). The whole environment and current birds can spread the disease. Bringing in vaccinated chicks could be an option. You would have to make sure that you practiced strict biosecurity until the chicks were at least 2 weeks old (it takes at least two weeks for the vaccine to make the bird build resistance). It is better to keep chicks isolated from Marek's for even longer, to build up a greater immunity.

Vaccination is best done when the chicks are one day old. Past that, they may have already been exposed. Marek's is extremely common and it is important to vaccinate as early as possible so that a chick builds resistance before it gets the disease. Vaccinating older chickens might work, but it isn't a gurantee.