I have two Pekin ducks that turned 3 weeks on Tuesday. I currently feed them Dumor chick starter/grower (20% protein) with added Brewer's Yeast. They seem to be growing like weeds and are messy (and sometimes rude) but so adorable! When do I move them to grower/finisher (15% protein)? The back of the bag suggests 10 weeks but I have heard so many people say 2 or 3 weeks... .which means now! Any suggestions?