Nine billion chickens are hatched every year in the U.S. Roy Curtiss and his colleagues came up with the idea of spray vaccinations, virtually eliminating the threat of salmonella for about one penny a chick.  Always interested in genetics, Curtiss began became fascinated with pathogens and and has taught about them in various fields, including biology and dentistry.   He eventually became a professor of veterinary science at the University of Florida and holds almost 50 patents.