Mixed flock needs new to ducks

[PeanutnMono]

I use 20% protein Dumor duck pellets for my flock of adult drakes. Any laying females would need oyster shell on the side. It's OK for ducklings from 8 weeks old [I have introduced it a little earlier when their starter crumbles have run out]. But if the ducklings are pekin, and particularly if they are jumbo pekin, I would give extra nutritional yeast to the ducklings until they are fully grown -- 8-12 weeks

Yes I have oyster shell on the side for the adult femalea... and they are khaki cambells.. would I still need to add extra yeast?