There are many different words for a group of ducks. A group of ducks is either called a paddling, a raft, or a flock, depending on where they are!
On land, ducks are called a flock or a waddling (because of how they waddle).
On water, they are called a paddling or a raft (because of how they float).
In flight, a group of ducks is called a flight, a flock, or a skein! A skein is a length of yarn, which is what ducks might look like when they fly together in a straight formation.