the national poultry improvement plan (npip) is a program developed to control diseases passed through the egg from hens to offspring. the npip was established in the 1930’s as a cooperation between industry, as well as state and federal governments. the goal of the improvement of poultry and poultry products. the npip was developed to eliminate pullorum disease which is caused by salmonella pullorum and was rampant in poultry and could cause up to 80% mortality in baby poultry. the program was later extended and refined to include testing and monitoring for salmonella typhoid, salmonella enteritidis, mycoplasma gallisepticum, mycoplasma synoviae, mycoplasma meleagridis, and avian influenza. the program was also expanded to include commercial poultry, turkeys, waterfowl, exhibition poultry, backyard poultry
for more information, refer to the usda page on the npip