Hey Mike, I'm not Azygous, but I will take a stab at your question. I am thankful to have a nice big population of wild turkeys. I don't know that the particular clump of sod that I give to my chicks has Marek's dz. in it.
I qoute Harvey Ussery in his book "The Small-Scale Poultry Flock" in reference to Marek's disease: "Marek's virus is to be found anywhere chickens are raised. Small home flocks, receiving normal exposure to universally ambient pathogens and managed to minimize stress do not require vaccinations to thrive. Ideal Hatchery, one of the 2 largest suppliers of chicks for backyard flocks in US says unambiguously on it's website: "Ideal Poultry does not recommend vaccinations for small flocks." (pg 50) "Apparently Gallus has already made a good deal of progress developing complete immunity to (Marek's)- some individuals have an inherited immunity, though others are susceptible and will succumb if under stress or heavy exposure. We can help the advance of natural immunity to Marek's in Gallus as a whole by culling all susceptible individuals who develop the infection. Looked at in this way, vaccination of whole flocks might be the WORST choice: It confers immunity to all potential breeders and thus masks the carriers of immunity and of susceptibility alike, making it less likely that the flock as an ongoing entity will increase natural immunity over time."(pg 221)
So, it boils down to how you choose to manage your flock. There is no right or wrong answer here. The only right answer for you is the one that you carefully choose after weighing the options and making an educated decision based on your comfort level. If your chicks are pets foremost, then you may choose to vaccinate them. If they are an ongoing flock, and you may at some point be raising your own replacement birds, you may decide to work towards natural selection. That being stated, you could raise chickens your entire life time, and NEVER have a visible case of Marek's dz. in your flocks. Though, you will most likely have some amount of sub-clinical infection present at varying times over the years that will never present with signs.
Oh the choices! Merely one of many choices and decisions you will be faced with over the next few years. Enjoy!
Edited by lazy gardener - 2/28/16 at 5:02pm