Hatched some chicks - too late to vaccinate?

[dpnation]

Hi there,
I have a flock of ~20 backyard chickens and just hatched a few babies for fun. I am just realizing now that you're supposed to vaccinate for Marek's on the first day. The chicks are 3 weeks old currently.

A few questions:
- Is it possible to vaccinate them now?
- What else do we vaccinate for? We are located in Vermont, USA
- Where do I buy vaccines in small amounts? (I've only seen large bulk providers and I definitely don't need 2000 doses)

The adult chickens haven't had any illnesses in the past year, but we did have a pullet that we got from a mail-order farm die from Mareks two years ago (I don't know if there's any risk lingering) so I am just overly cautious as we were pretty sad about the one chicken getting sick from something that was preventable.

Thank you!

 

[nuthatched]

Too late for Vaccinations, mereks vaccine only comes in large doses and it doesn't prevent the disease just keeps the mereks tumors from growing so they could have it and spread it.