The diseases that the NPIP is most concerned with are the bad and easily transmitted, chronic diseases that don't have effective vaccines. So if you are buying chicks or hatching eggs from a NPIP flock you are also buying years and years of careful chicken husbandry. But the above does not mean that the hen and/or rooster that is responsible for producing the hatching egg or chick has been tested, although they may have been.Thanks for all the info folks .... The question i should of asked or at least researched is whether or not NPIP flocks are vaccinated more so than not.....