When drakes and ducks mix, it can get interesting, to do keep a fence between them. With some supervised time together, you can decide if it is working.
Ideally, and for the ducks' (girls) well being, there need to be more ducks. Drake to duck generally is recommended to be no less than 1 to 3, and 1 to 6 is better.
Drakes get really . . . well . . . they can hurt the ducks. Some drakes are nicer than others, but some are just really tough on the females.