I'm seeing two drakes and 4 hens. In your 4th photo with four ducks in the main frame, the two behind are the drakes- I believe.
You have a very beautiful flock!
do they quack? Any with a whispery rasp are drakes, any who quack are hens-
If you arent sure, could you get close up photos of each duck so we can get a close look at the feathers around their tails-how old are they?