Before you choose to vaccinate, you might want to view this: http://www.pbs.org/newshour/updates/tthis-chicken-vaccine-makes-virus-dangerous/
If you have wild turkeys visiting your yard, they carry a less virulent strain of Mareks, and will confer immunity to your flock simply by exposure to...
Ed, many folks do recommend vaccination for Mareks. But there is an other side of the coin. The vaccine does not prevent the disease. It prevents the complications from it. Turkeys carry a less virulent strain of Mareks, so if you have a population of wild turkeys, or even get some domestic...