Big shout to the University of Illinois for forever ruining the best bath toy pastime ever -- the rubber ducky. Because OF COURSE they had to cut into them and discover a ton of bugs and bacteria inside -- the kinds that cause hospital-grade infections.
But seriously, I'd say either replace your rubber duckies regularly, or just ditch them. Y'all don't need to be getting sick infected kids from a plastic duck. (Although, let's be real -- your 2-year-old is probably playing with an iPad in a bathtub at this point.)