Yes, I had two of the dead birds get necropsies and I also did DNA tissue samples to confirm Marerks.
They don't have to be chicks, they can be grown pullets if they are vaccinated.
I hope someone can give me a little advice. I had Mareks outbreak in my flock, and it killed 4 out of 5 birds. Now I have a lone bird. Now i know chickens are a lot happier if they have company so i am wanting to introduce a new friend to the remaining hen. I'm just not too sure how to go about...