Any food other than the ducklings starter feed they will need grit [chick grit is best when tiny.]
If it's safe to feed to chickens then it's okay for ducklings you just want to make sure to not over do since their feed is where they will be getting most of their nutrients.
I really would stay away from beans unless it's very cooked green beans with out strings. And not canned unless with out salt. Peas seem to be the favorite among ducklings/ducks.
Good All flock feed is best for our feathered babies it has all essentials they need especially the niacin.
Can we get a pic of your little one?
:welcome
Corn is fine to give in small amounts it can put on pounds so you don't want to feed a lot. I know quite a few members who feed their flocks chick starter /grower as their sole ration I don't see any problem with it but you want to make sure she gets enough niacin too which chick feed doesn't...
You talking about long French green beans? I think those are fine. I think the beans in the thread means like dried beans like pinto or other dried beans. Been a while since I looked on the thread though.
Sounds awesome. @rory63 Welcome to BYC!!
Interesting what ever part of the world we live in our birds have access to tasty things that are good for them.