Not really sure about your campbell duck right now it does look like a she.I think the drakes start getting a green tint to there head also.You can tell male and females by there quacks. a female is very loud QUACK QUACK a male is a lot quiter with a raspy quack almost like whispering. Hope this helped. It sure helped me when i first got my ducks/You have some pretty ducks.
not boy and girl hopfully I can find a not so exspencive female duck as an adult online somewhere 
bahaha I'm silly. but yes I wil lsee if I can find them some girlfriends~