If they show up to "depopulate your flock" bcuz there's been avian flu in the area, you have the right to stop them and get your birds tested first. It was a very short window given, not exactly sure if 24 or 48 hrs, so you should connect with your vet now for a quicker response if necessary. Also note, if you have pet birds - parrots, they will depopulate them as well.
@LindaWisner Since I have a small flock it made more sense for me to vaccinate them and be able to show proof.
Completely different story when dealing with a commercial gig.