My two are tiny little Australian Spotteds, in between a call and a female mallard, size wise. I'm hyper vigilant about pesticides where they play. I've been using their used Aspen bedding as mulch for our yard, and it has made the soil nice and soft (finally!). Since the ground is no longer impenetrable, I've been digging lots of holes and planting a lot, and they are expert earthworm and bug eaters. They do still eat some of their feed, just not nearly as much as they were eating. They won't be a year old until August, and since I'm not working right now, they're getting their first multiple hour long play sessions. We have lots of predators out here, so I stay with them while they're playing.
Yeah, they should be fine then . I wanted to make it clear in case anybody reads this that contrary to popular belief just because medium/heavy ducks are outside doesn't mean they are getting their niacin intake needs.