Welsh harlequin question- sexing

[Chloesmama]

Hi! I have 2-13 week old Welsh harlequin ducklings and am waiting to see genders. I got them from a feed store and was told they were female. One grew faster and is still larger. The big one also doesn't quack nearly as much, and has a deeper voice. The larger one also has been more assertive and protective from the beginning.
They are both showing some mating ritual behavior (flattening on the water, biting tails, climbing on each other's backs) but I can't tell them apart when they are so frisky and moving so fast, so I am unsure which is doing what behavior.
Neither are showing any color signs of being a boy and I was just wondering when the head changes color if they are male?

Anyone want to share their experience?

Thanks

 

[Floof]

Could you post some pictures? How old were they when you bought them? In the first few days they are sexable by bill color.

**edit to say they are also sexable by bill color later as well. The girls will gradually darken to black and the boys will lighten. My 9 week olds have already had their bills show the color change.

 

[Chloesmama]

Here they are. Really hoping for girls. We got them at 2- 4 days and they were supposedly both female

 

[Knighstar679]

The ones pictured are all girls. They all have a dark Bill and not an olive colored one which would be males at that age.

 

[Chloesmama]

Great news!!! Thank you