I don't see any drake feathers, but the best way to tell is by their voices. Females are noisier and make the iconic "quack" sounds, while males are generally quieter and have low raspy voices. What do yours sound like?
The white cambell is as loud as they get my khaki cambell is not as vocal. It's my white cambell that's climbing on top of my khaki cambells back and biting it's neck is this normal behaviour if they are both females xx