But, my experience with chickens, turkeys, cows, pigs, and sheep is that they will forage, but a heritage breed is going to be better at it than a factory farm breed. I don't know if there is a duck breed like that.
If you have things available for them to forage, they'll do it.
My project thread Agriculture collects solar energy two-dimensionally; but silviculture collects it three dimensionally.
I think its probably both. But my birds all turned out to be expert foragers. Why? Because I didn't baby them. They went straight out onto grass from day one (I had a little pen half covered and I turned on a heat lamp at night). I'd toss them the occasional hand full of myciliated rye but I never put it in a dish so they had to pick it out of the ground (much more natural than feeding from a dish which IMO encourages dependency) Ducks from day two or three will hop straight into water and start diving around. I say let them (and give them a heat lamp to dry off under). Put some good ol' mud at the bottom. MY duck is a great forager now - though chickens and especially Geese take to it the most naturally in my experience,. Good luck!
Landon is spot on here with the answer being both. We bought ducks as babies last year that were incubated (Runners and Ruens) and we let a few Muscovy mothers hatch some out also. While the Muscovy babies seemed to be less stressed and better foragers in the beginning, the others soon caught up and learned the ropes. The key is to not baby them as Landon stated. You will not find out who is tough or a good forager if you pamper them.
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