Train ducks to eat fresh in-shell sunflower seeds

I grew sunflowers for my muscovy and kakhi campbell ducks.
I broke some out of the flower and gave the seeds-in-shells to them.
They try eating a few if I give them my "I have a treat for you" call. But then ignore them.

A few years ago the chickens figured it out and went after them.

Is it reasonably possible to teach them that there is good food inside that shell?

My ducks just aren't as motivated/inspired by food scraps as my chickens. Chickens are more used to scratching and pecking and tearing things apart. Ducks tend to just gobble things whole--they don't process them. So, in general, I don't try throwing food scraps to my ducks--they just don't appreciate them. I give my chickens everything and treat them as composters while my ducks are slug/spider/pest control.

As ducks can be trained to eat acorns, as seen in the following video, I guess they could also be trained to eat in-shell sunflower seeds. Can your chickens teach your ducks to eat the sunflower seeds?
My approach  would be to give the ducks access to the feed from an early age, and to limit the other feeds for some time.
Do they get enough grit? Stones are really important in digesting harder feeds for birds.



My muscovies loved slugs, as I gave them some from an early age. Some sources state that muscovies don't eat slugs.

My experience has been much the same as Nicole's. About the only kitchen scraps or ducks have ever really liked were raw leafy greens, (like the bug-chewed or rusty outer leaves, and such). So, I'll save those for them. The chickens love the other stuff, but the turkeys are kinda picky, too.

I have seen somewhere that Muscovies are genetically geese, and would therefore be grazers.

The phylogenetic tree of ducks and geese below shows muscovies are more closely related to ducks than geese (geese are in the lower rectangle, muscovies are higher up, Cairina moschata, and the ducks we know are Anas). They can also interbreed with ducks, producing the mulard, which is infertile.



However, I really like the saying: "Muscovies look like ducks, behave like geese, roost like chickens, and have breasts like turkeys"