How Long to keep ducklings on starter feed

[Big D Tapp]

I have several Cayuga ducklings about 3 to 4 weeks old. How long do you feed them starter feed before switching them to a waterfowl feed? I have several adult ducks and 2 geese about 2.5 months old and I feed them a waterfowl feed, but I am not sure they don't eat the layena for the chickens during the day. I know they feed on grass and bugs and whatever else they find in the yard.

 

[chickens really]

I feed starter till they get their feathers in...Then I feed grower till 4 months old....or after their juvenile molt....
I feed Duck food though....