For reference, they will be kept inside until they are at least at their juvenile stage and too big to stay inside, that's why I wanna know if I could still vaccinate them.
So I have three eggs that are most likely going to hatch tomorrow, but I forgot that Marek's was even a thing and I remembered that I should probably vaccinate for that since I intend on selling most of the chicks! I have three in this batch that are gonna be hatching, and my question is that if...