This falls alongside my line of thinking too. I never quarantined either, I figure if the bird's immune system is too weak to fight off whatever it is, then I don't want that strain anyway. Same reasons I stopped medicating birds way back when.You can quarantine til hades freezes, but if you free range it is all for naught. Unless of course you have a forcefield dome over your property so no other life forms can enter.
Now if you never free range (including tractors) and keep your birds locked up in a coop or cage then you might succeed. Of course as always, it's just my opinion and I'm kinda use to being wrong.
PS, chickens are pretty dern hearty animals. They survive small kids, owls, hawks, dogs, coyotes, cats and other chickens. They're omivorous but are decended from raptors.