One of my friends recently told me that if a bird is vaccinated for Mareks disease that it will shed the live virus in it's poop and give it to the unvaccinated birds. Is this true? I have vaccinated and unvaccinated birds that range togther in the same barn like they have for months now and they are all fine. The same person said that I could not show vaccinated birds because they would transmit whatever they were vaccinated for to all the unvaccinated birds. I am signed up for a show in October and I am getting kind of nervous about this so I would love someone to answer my question. I love all my birds and would hate to see them get hurt do to human error.