According to Bob Creamer, Hillary Clinton’s campaign coordinated with the DNC and the non-profit organization Americans United for Change to have people dressed as Donald Duck protest — and even to instigate violence (a tactic known as “bird-dogging”) — at Trump/Pence events.
Further, Creamer said that the bird-dogging duck was Hillary’s own idea:
In the end, it was the candidate, Hillary Clinton, the future president of the United States, who wanted ducks on the ground. So, by God, we would get ducks on the ground.