Drake or Hen Rouen confusion

[Llh1]

My Rouens have me puzzled by the week, they change so drastically! So, mine are 9 weeks. When do drakes get the white ring around their neck? Here are pics of my 2. What do the experts here think?

 

[jdashca]

I've never kept Rouens, so I don't know about the white ring, and I don't think they get the curly drake feather until they're at least 2 months or so. The first way I can always tell with my ducks is by their voices - the females develop a loud quack whereas the males' voices turn soft and raspy.

 

[quackers619]

looks just like my female Rouen accept her beak is black .......but best way to tell is by the noise they make. It was easy to tell male from female before my drake got his curly feather