I just spoke with a guy from Twin City Poultry Supply. He said he has been raising poultry for 30+ years. He told me that if the chicks hatched in an incubator, he would vaccinate; but, if the mama hen hatches the chicks, then there is no reason for the chicks to get vaccinated as they are pretty much already exposed. He told me he would hate to take my money when he wouldn't vaccinate them if they were his. I love dealing with honest people.
This is about right-- if you have Marek's disease on your property, and want your broody hen to raise chicks, they will be exposed nearly immediately. There wouldn't be too much of a point in vaccination, unless you have reasons to think your momma hen is not a carrier (if she was ever exposed, she IS a carrier). Still,
please understand that there is a risk in this and the risk might be higher than incubator-vaccinated chicks. You may experience some loss of the chicks depending on the strain of the virus on your property, and how good momma's genetic immunity is that she's passed on to the chicks. There are a lot of factors at play.
Chickengeorge - I'm no virologist but I do know that the Mareks virus belongs to the family of herpes viruses which works differently from most other viruses.
You may know that among humans there is a sexually transmitted herpes virus which causes outbreaks in the infected individual but lies dormant most of the time. The individuals who carry this virus can infect their partners at any time. Also cervical cancer is caused by a herpes virus, so are warts - very different disease manifestations compared to the diseases you use as examples like polio and influenza - these work completely differently.
Salmonella pullorum is a bacterium - not a virus and a totally unrelated process needs to be used to immunise birds.
I conclude that the comparisons you use are invalid.
Have a read-up in the scientific literature about Mareks disease, Mareks virus and Mareks vaccine and you won't find anything that contradicts the statements I have made above.
This is a good comparison, and as a Marek's research nut, follows with everything I understand about the virus. Further, I have recently read a study that suggests that vaccination does NOT reduce the amount of virus shed by exposed birds (it is cited in my research in my signature).
So, one must assume with Marek's that any bird, regardless of vaccination, will shed the virus once they are exposed to it. Herpesviruses are very good at creating latency and shedding even with no symptoms shown, for the lifetime of the host. Marek's is just that much more nasty, given that it is airborne in super fine dust particles, and no contact is needed.