Very interesting!! I would habe to say yes, the broody hen is Marek's positive. I don't have a brooder per se, but a bin I set up with a heat lamp. I've never had fresh hatched chicks before, will this setup be sufficient should I go ahead with vaccinating them?I heard chicks could have antibodies from the hen that is Marek positive, but I'm not 100% if it's true since it's just information from a website. If it is ture, yes, you can let your broody raise them and vaccinate them right away. The antibodies should protect them for a couple weeks, IF the eggs came from a Marek positive hen. I have Marek in my flock too, so I only order vaccinated chicks and will seperate them for 3 weeks before trying to give them to my broody. At 3 week old, the broody may not accept them though.