I just placed my order for our next batch of meat birds and threw in an additional 4 layers to add to our established flock. Currently have 8 pullets and 1 cockerel that were NOT vaccinated for anything. This time around, I opted for the Marek's vaccine. (There seems to be a divide on the forums as to whether or not it's a necessity.) My question is, now that I've had these new birds vaccinated, do I need to vaccinate the birds we already have? I need a simple yes or no answer as I was getting overwhelmed and confused while reading about Marek's and how the disease works among vaccinated and unvaccinated flocks. Or should I just go ahead and vax the current flock just because? What would you do? Thanks in advance!