sorry if this is obvious, but I have been searching all over the internet, and BYC, and still can't quite get a definite answer. Why can a chick only be one day old to be vaccinated for Marek's? Is this because it needs to be done before it is exposed to the virus, which is almost everywhere? Also does a hen that has been vaccinated for Marek's, provide any immunity to her offspring? (I am guessing not, since the virus mutates.) Just wondering because I have Marek's on my property and a little bummed that I won't be able to hatch any of my own chicks, unless I most likely hatch them out using an incubator, and I order the vaccines and administer myself. I would really rather have a hen hatch them out. Oh well. Thanks for any imput!