Since nutmeg is a sex linked color if the male doesn't show the color and he produces offspring that are sex linked that means he carries it. When it comes time to give his share of genes to the offspring he could either give the sex linked nutmeg gene, or the one that is not the nutmeg gene...
If you are talking strictly about sex linked genes then yes females cannot carry any of them.
Females can carry recessive genes.
If I remember correctly nutmeg is a combo of the chocolate and buff gene, so if the male of your ducklings was nutmeg and the female was grey than you would get...