I would certainly offer oyster shell to them free choice...the drake won't eat it but the ducks will as they want/need it. As for the layer pellets, the drake doesn't need the extra calcium... but I think that some here at BYC say that the drakes eat it along with the ducks. Not sure where...
I have two pekin ducks...I have had them since they were a day old. One duckling had a bill that was pink almost purple in colour (hence my daughters calling her "Purple beak") and the other was the normal bright orange. "Purple beak's" bill is still pale and pinkish and my only...