Rouen or Mallard? And sex?? - somehow posted in Hatching?? Oops!

[Katybird80]

About a month ago I purchased 3 ducklings at my local feed store. I was told (and signage indicated) that what I was buying were 2 female Mallards and 1 male Rouen. I have been reading online about eye-stripes and the difference between the 2 breeds.. and now I am really confused. I know that Rouens are bigger than Mallards, which makes sense with my 3 (see photos - the largest, by about 2x, is the “male Rouen”. The others are “female Mallards”) but they all have only 1 eye-stripe and the 2 females are starting to have that green iridescent coloring on head feathers where the male does not. They are supposedly all around the same age or within a day or 2. I am really just confused at this point. I do understand that they have not finished feathering out and it will probably be so much easier to figure this all out once they do but does anyone have any thoughts here??
FYI- 1st pic is male, 2nd & 3rd pics females, 4th & 5th pics for size comparison

 

[Katybird80]

On a side note, you can almost see the green iridescence on the heads of the females in the pics.

 

[indianaducks]

My female mallards looked slightly green as they grew out of their duckling down. But they are definitely females. And my male mallards are now definitely male. I had to wait for their quack (or lack there of) and now their actual feathering.

 

[fatty and friends]

2 mallard hens and a rouen drake! my rouen girl had a greenish head around that age but now she is older and it’s completely gone

 

[Katybird80]

Thanks! I guess maybe I should have a little more faith in my local feed store! What about the eye-stripe(s)?
And will they/do they have different vocalizations as adults?