If the protein in your starter food is over 18%, you definitely want to switch your duck over to lower protein grower. You're aiming for 15-16% protein. Start watching for shakey legs also, to alert you to any niacin deficiencies.
21 weeks to sex by feather color sounds about right. You can sex by drake curl between 12 and 16 weeks, and you can sex by quack at 8-10 weeks.
21 weeks to sex by feather color sounds about right. You can sex by drake curl between 12 and 16 weeks, and you can sex by quack at 8-10 weeks.

