I suggest checking out Metzer Farms website there is lots of information on caring for ducks including feeding suggestions. That is basically what I go by. I feed Mazuri feed even though it is very expensive but the ducks do not waste the feed as they did with the pellet feed I fed. So for the difference in waste cost per higher feed bag cost it turned out to be close enough to use the higher priced food. I feed at present breeders formula year round and it does good for me.