Several sources said if you have a vaccinated flock you should vaccinate any new introductions.
Vaccinated bird will NOT infect newcomers UNLESS they are hiding the disease.
Since I hatch my own birds.. (breed selectively) There has been a gene identified that does give natural resistance to MDv and I am breeding for resistance instead of vaccinating everyone for the rest of my life which keeps the company making the vaccine in business but does nothing to actually better manage the disease, which they would have caught at your place since they were vaccinated from hatchery. I MIGHT wanna know??
One gal I know of..
@Folly's place keeps both vaccinated and not birds.. considers those not vaccinated to be the canary in the coalmine with regard to MDv..
It really is a personal choice. I also have not YET confirmed Marek's at my place. None of the birds sold from here were reported back as having caught or succumb to the disease, but I did get reports from one person who said my Silkies were the only ones left.
Maintaining good personal bio-security, keeping a closed flocked and buying from only NPIP sources when you do (despite Marek's NOT being tested for or considered re-portable), and don't roll out the welcome mat for wild birds by putting out feeders, etc.
Since you have a little time.. maybe decide how YOU feel about the vaccine and consider skipping it, or maybe doing half the chicks.. do they happened to be sex linked in anyway? Are you selling or keeping them? You might also call your local agriculture department or state poultry lab (contact link follows) and inquire as to the rate of Marek's cases in your location! Are you going to be eating your extra roosters or did you have another plan for them?
I ask because if you will eventually eat some and therefor basically have to accept death as part of the process.. then MAYBE losing or culling a bird due to Marek's (IF it's at your place) wouldn't be the most devastating thing ever.
For folks who have had a Marek's diagnosis and aren't breeding in any manner, or will not be considering harvesting extra boys to feed their family.. 100% vaccinating and quarantining from outside influence until it's considered effective would likely be their best option to be able to continue keeping incomers with the least amount of drama and completely makes sense. Even when MDv is present.. not all birds will succumb.. it MAY depend on how virulent the strain.. but I have seen reports as low as less than 10% loss in diagnosed flocks. Marek's stinks but it isn't quite the scary monster it's been made out to be. Learning about it broadens my understanding of this Covid thing.. helping HUGELY to keep things in perspective and not become fear mongered into a panic. Try not to let fear run your choice either.
Please note I am NOT an anti-vaccine type person. It's more like attention detail and want or NEED to know the WHOLE truth.. And in the case of Mdv vaccine hiding symptoms but NOT preventing the disease.. to
me that's a lie I can live without.. As you can see, I've had plenty of time to decide how I feel about it.. thank you for letting me share. It's important to always do what YOU think is best for YOUR flock, according to the knowledge you have at the time. Sometimes we learn something new or have an experience that changes our minds.. Switch it up and see, again. We keep doing our best.
Hope you're crowded with lil' peepers soon!
ETA:
https://www.aphis.usda.gov/animal_health/nahln/downloads/all_nahln_lab_list.pdf
Georgia Poultry Laboratory Network
3235 Abit Massey Way
Gainesville, Georgia 30507-7745
Phone: 770-766-6810
IAV-A, ND
