It's the National Poultry Improvement Plan, a govt program where your birds are tested once a year, I believe, for Pullorum and Typhoid and sometimes Avian Influenza. You cant buy birds from non-NPIP sources, I think, and other rules. It gives a buyer some sense of security when purchasing your birds/eggs, but there are so, so many other diseases and if someone just doesn't want to follow the rules, they are rendered meaningless. One case in point is an NPIP breeder in Washington State who has been responsible for spreading a terrible disease, ILT. The state doesn't seem to care enough to do anything about it, last I heard. I may one day do it, if people seem to want that, but for now, I dont see that much need for it unless you show your birds or have a big business. That's just my take on it. I'm sure others think it's quite beneficial and in some ways, it probably is.
Gator, I hope all goes well with yours.