I was hoping to be able to keep them together. I only have the 1 Cayuga drake, 3 Cayuga hens, 2 crested Pekin hens, and 1 crested mallard hen. So far only the crested mallard hangs with the Cayugas, but I am betting that when the drake reaches full sexual maturity he will over breed the 3 Cayuga hens and I'd like the cresteds with him to help spread his attentions.
I know that on the goose threads they paint the vents with food coloring and match the egg colors to the painted vent to be sure which hen laid which egg. Think something like that could work? I'd have to repaint their vents every few days. Think the black feathers of the ducks will hold the food coloring as good as the lighter colored geese feathers?