hello, i just started hatching my own chicks and I have decided to vaccinate for Marek's. I ordered a bottle of vaccine from jeffers, as recommended by folks on this site. My question is this: do i only have 1 chance to vaccinate all the birds? I have ordered more losses than i need right now, hoping to save it and use for later hatches. I read that the vaccine is no good after 2 hours, does this mean that i only have one chance to vaccinate ALL my chicks and after that whatever is left i should throw away? I hope not... Also, is it ok to vaccinate chicks that are past the 1-day mark? thank you in advance!