My 2-year-old ate raw ground chicken, is there anything we should do as a prophylactic measure?

Watch & wait: There are germs associated with raw chicken but they may or may not be present or cause any problems. Onset of diarrhea associated with fever or bloody diarrhea should prompt a doc visit & stool culture. Some of the germs are innocuous and some you don't necessarily treat if they show up on stool culture. Abx sometimes prolongs the duration a kid carries the germ in his/her gut.

Raw chicken: Nothing to do now but monitor for vomiting, diarrhea and abdominal pain. If it starts then pedialyte.