I've never seen it posted either at their store. The one time I bought chicks at TSC, they were bantams, and 2 out of 5 survivors we culled for suspected Mareks. I haven't bought from them since except for some pheasant.Hmm it seems this may not be the case. I can't find anything anywhere that states they do or don't vaccinate their chicks. I know Hoover, one of their main suppliers, does it upon request but not by default. Maybe it's different for the ones they send to TSC though.