So if my flock becomes NPIP certified, then I can not add chickens to the flock unless those chickens are NPIP certified too? If I was to add chickens from non NPIP sources then it would nullify MY NPIP, right??? & if I sell any of my flock or eggs, I need to prove that they are NPIP too? It seems like alot of the folks here are not NPIP. My flock was tested last week & they were clean, so now its just a matter of a bit of paperwork to have them be a NPIP flock.