How to feed mixed flocks??

[BlessedChaosHomestead]

Is 45mg/lb of Niacin a good number?
I found https://www.kalmbachfeeds.com/ food today at one of the Co-ops around me & so far from what I was told & what I've seen their food seems to be decent quality for the price. (They even offer Non-GMO/Organic options.)
But their Flock Maker & Maintainers states it has the daily requirements of Niacin for Ducks & Geese.

 

[ShannonsChimkens]

Have had a flock of multiple birds for several years all on 20% starter/broiler/all flock pellet. Emus, turkeys, chickens, guinea and duck. All do great. Oyster shell on the side. Grubs and veggies from time to time.

Your flock will do fine. The niacin tip is a good one. The ducks will have issues if they become deficient.