Hi I got 2 pekin ducklings from ideal 1 week ago. They are growing like crazy even though they don't seem to eat much. I am looking forward to giving them treats. So, when can I give them treats such as: lettuce, koi food, tomatoes, applesauce, and strawberries? I already gave them some mashed bananas and they loved it. Also, should I start giving them grit? If so, what kind? Thanks!