At what age do Khaki Campbell Drakes get their Adult plumage?

[Mattsculpt]

I have two possible Khaki Campbell ducks. (They might be dark Khakis or even from a Campbell / black runner cross) They hatched out the last week of June and are now 21 weeks old. At least one is laying eggs.
They both have pretty much the same feathers, though sometimes one looks like it has a curly tail feather.



I can't tell by the quack because both are mostly quiet but if alarmed make a waak! sound. My other ducks are only 8 weeks old so I know they aren't laying the eggs. So do I have 2 ducks or a duck and a drake? If I do have a drake at what age will he get a green head, solid khaki body feathers and a dark tail?

 

[Finny]

I have a khaki drake and he is a little under 16 weeks old and he has a curled tail feather and has his raspy drake voice. He is starting to get his dark tail and head coloring. I will take a picture tomorrow to show you what he looks like. If yours are 21 weeks old I am thinking they are female.

 

[Mattsculpt]

Thank I'd appreciate that photo. I know how old they are because I hatched them out. I didn't know when the males changed color. With their dark heads it was hard for me to tell if they were males or females until the eggs arrived.