So after what I'm almost positive was Marek's, I've lost 7 out of 8 of my chicks. I'm now left with 1 chick from that group and two hens. I believe my hens may have been vaccinated and carriers, because I hatched the chicks in my incubator and they didn't show symptoms until a few weeks after I put the with the hens. The last chick is doing really well, but I'm not getting my hopes up. My hens are perfectly fine. I'm looking for information on potentially adding vaccinated chicks/chickens into my flock in the future. What has worked for other people? I'm so afraid of losing birds again. Watching my chicks rapidly become paralyzed and die within a week or two broke my heart. Is it possible to introduce adult chickens that were vaccinated as chicks? I'm mostly just wondering what other people have done and experienced.