My drakes always have to try anything I put down but they lose interest pretty quick. Eating a small amount of oyster shell will not hurt him.Hello I have a 6 almost 7 month old female mallard this she is about ready to lay her first egg. Of course I want to make sure she is getting adequate amounts of calcium I however don’t want to incorporate oyster shells for any on the side dishes because I have a drake and he basically will eat everything. So I wanted to give her supplement orally with this reptile powder mixed with water in a needless oral syringe but I’m not sure how much female ducks need she is 2lbs. I appreciate the help with the dosage :]