Should I Vacciante?

YES! even though it won't fully ensure they'll never have that illness It's will definitely help.I got the marek's disease vaccination for all my chicks,and would've gotten more if the hatchery had them.

Marek's is everywhere.  At the very least vax for that.  I learned the hard way.

You could go broke vaccinating for everything under the sun that a chicken could ever get-some diseases are just not all that common. I vaccinate for nothing, never have, have never encountered contagious disease here at all. Most backyard flock owners who practice reasonable biosecurity and good common sense really don't need to do so, IMO.

It's your call, of course, but just know that some vaccines will actually make the bird a carrier of the disease you are vaccinating for you and you'll always have to vaccinate for it for the rest of the time you own poultry. You'll have to do research on this. And some need boosters, too.
 

ETA: One misconception is that Mareks vaccine prevents a bird from contracting it. It only prevents the tumors associated with it from forming, as I understand it, doesn't completely prevent the disease.

If you show, that could be somewhat different, however, there are some aspects to consider about vaccinating your birds. If you sell them, you will have to be sure people who buy them who may not vaccinate for certain diseases understand that their birds could be at risk from yours. This vaccinating thing is not as simple as many people believe it to be-so many things to consider. Just do your research. I am not an expert on this subject and certainly don't claim to be.

No, I do not show because of the disease risk associated with it. There were folks in Washington state whose birds contracted ILT a few years ago at shows from NPIP flocks who were infected with that disease. When you start vaccinating for many things, you can never stop.

I can't speak for the other vaccines but Marek's is safe to give and doesn't leave you with a carrier.  If I had known this last year, I would have saved myself a terrible year of heartache.  As for practicing biosecurity, I never had a chance.  I was just building my flock, the first in 30 years, and brought in a chick with Marek's.  The rest, as they say, is history...and so are 30+ more of my birds!

If nothing else, vaccinate for Marek's.  All of my chicks that I bought vaccinated and isolated for the appropriate time are still alive and well....I have lost almost all of my original flock.