On the new pic the eye stripe appears much bolder than I realized maybe a Rouen is a possibility . Not runner or khaki . I think I had the wrong breed in mind for golden 300.Can you post a pic of it standing up. Also where did you get it. I ask because that can narrow down possibilities or if a cross is possible. Not a Rouen they are similar in color to mallard. Golden 300 if I'm no mistaken are white. Brown ducks include runners and khaki for starters.