Thank you, Glenda.
Please do not confuse Pullorum/Typhoid with Marek's Disease, which is spread by dander, is a long lived virus, and while birds are carriers, they may show no syjmptoms, and it may or may not be a virulent strain of the virus, affecting few of the birds of a flock--or it may be a very virulent strain and many birds will die. It could be carried by a healthy appearing bird at a show, and an unprotected bird, could be infected, but it is not a high risk for show-birds. It requires responsible exhibitors!

Marek's Disease is NOT carried in the eggs, the chicks are not infected at hatch unless exposed to the virus through the dander (chicken's body-"dust") of any carriers in the flock. Hatchery or incubator hatched chicks, are unlikely to ever be infected, so vaccination of those chicks is a very good immunity expectation and worth the little extra cost. By vaccination at hatch, chicks may have a long term immunity to Marek's. Even unvaccinated chicks from hatcheries, will not be bringing the virus with them--but may be exposed when they arrive at a premises where carrier birds have EVER lived. Few chicks or young birds will exhibit any symptoms before several months of age, the pullets most often just at point of lay. The virus is considered to be world wide and any unvaccinated (or naturally immune (?) bird is always at risk--any age. CJR