There's a godd possibility of that happening. If nothing else, you can do what I did to my pair of lavender orp hens... put them down and burn the carcasses. I wasn't going to be responsible for spreading disease.thanks, I'm selling them in small groups to people who are only going to keep a closed flock for eggs.
My only concern is what to do with my Lavender Orpington trio. Given the value of the roo and two young hens and their eggs I don't know if I can sell them and trust they won't be used for breeding.