I went to buy some duck grower today from the Campbellford Co-op, the Duck Grower is 18% and its just about the only thing I can get that is non-medicated. Now, I realize that to prevent angel wing I should be feeding 15% at 4 weeks (which they are now), can I feed the 18%, restrict it, and feed greens on the side (they're out during the day on the lawn, and will be out in their duck house by the end of the weekend). I could take the food away at night, and give it back in the morning much like you do with Meat chicks?