AmazingRachel
Songster
Just saying, if given the option, I would always vaccinate against Marek's. It's better to have some protection than none. And no, the vaccine does not cause autism in chickens 
https://www.pbs.org/newshour/science/tthis-chicken-vaccine-makes-virus-dangerous

https://www.pbs.org/newshour/science/tthis-chicken-vaccine-makes-virus-dangerous