I did this by myself for the first time nearly 4 weeks ago with 15 chicks. The vaccines come with a small bottle of the vaccine itself and a larger bottle of the dilutant. They get mixed together.
The directions I had said they should be vaccinated at the hatachery or at 4 days old, I did 4 days. The toughest part is parting all the down. I held the chick in my left hand facing away from me; I used my index finger over the top of their head to keep their head down and with my thumb, parted all the fuzz. It was only .1 cc per chick so it isn't much and I only had a few that were really wigglers! A vet said I could use the same needle for all 15 chicks. I used needles I purchased from my pharmacy that were a very small gauge.
I'm glad Mareks vacs don't have a booster. I couldn't imagine doing them now (though it would be much easier to part feather vs. down and the necks are larger). I'm gearing up for the one month Newcastle booster.
