So sorry for you diagnosis. I agree with Dawg, there's no way to guarantee that your birds were not be a danger to other people's flocks. I occasionally get hatching eggs from others, but never birds apart from chicks from reputable hatcheries, and I never go to swap meets.
Some infections can also be carried by wild birds, and the only way to truly prevent these would be by keeping your flock in a strictly indoors enclosed structure. I am not willing to do that myself and so there will always be some risk.
Some infections can also be carried by wild birds, and the only way to truly prevent these would be by keeping your flock in a strictly indoors enclosed structure. I am not willing to do that myself and so there will always be some risk.