Scovies are very quiet.... both boys and girls. No quacking fm these two.... the girls have a sweet coo, chirp and the boys will hiss and huff. How old are these two? They look pretty young yet. At about 4-6wks old you should be better able to tell the hens fm the drakes. The drakes will have really big feet and start outgrowing the girls a lot. The drakes end up being twice the size of the females. Also, the drakes will begin to develop their caruncles sooner and will have more.
Cute ducklings by the way.
i agree with keeperofthehearth muscovys are great i live on 800m2 and breed to show my birds i have 21 birds at the moment and the neighbers dont even know i have them keep on top of housekeeping and there will be no problems . mick