So glad you asked!
I took this picture on Monday of the duckies. Both Khakis are the same age - this week turned 14 weeks old.
The duckie in the top part of the photo appears to have gone through the change, but retained brown coloring. Has a double tail curl - SOMETIMES!!! It's so random. Usually after a playful swim, the tail feather curls are there. Then they disappear. Talks often - both duckies do. Bill has maintained the grayish/dark color.
The duckie in the bottom part of the photo has the gray/almost white belly, the BLACK tail, a greenish bill, the black head with beautiful irredescent green (like a Mallard duck). Talks a lot. They both usually talk at the same time, so it's hard to understand them AND hard to distinguish if there is a difference in sound. Did I mention the two Pekins join in the conversation and drown them out?
So whatcha think?
I'm pretty confident the duckie in the bottom part of the photo is a guy. His drake feather comes and goes too.