I am feeding my ducks (about 3-4 weeks old) Dumor Chick Starter. I just today started giving them Brewer's Yeast on top of their food. The protein content in the starter feed is 20%. Is that too high? I have read you can add oats to the feed to lower the protein for ducks. Do I need to start adding oats and brewer's yeast to the food? Can I just mix up a bunch of oats and yeast in with a bin of their feed to make it more even? If so, what is a good ratio of food to oats and yeast?? Thanks so much!