That's not what actually happens. Here we have unvaccinated birds who were hatched here, and vaccinated birds from hatcheries, all together, and have managed this way since 1995(ish). We haven't had Marek's disease in our flock, because we've been very paranoid about biosecurity, and we've...
Vaccinated chicks need to be totally isolated from possible exposure to the disease for about two weeks; hard to do at home if you have Marek's disease on your property.
Otherwise, it's ordering a vial from Jeffers or some other source. It can be divided into four amounts for a total of four...