I have to agree with this comment, far more likely. And these are also probably the same people who are then contracted by the CDFA to violate people's rights with unlawful search and seizure and destroy other peoples home flocks that stay in one place and aren't spreading any disease.Again, I'd really like to see any studies on cross-property airborne transmission.
Far more likely is that commercial flocks were contaminated by workers dabbling in or attending cockfights.