Actually it's not me who has them, but a friend of mine who works at an animal shelter that asked for help. And I don't think she'll be keeping them, most likely they will be set free once they're strong enough.
I would have never guessed that, but since all of you agree there must be something to it. Thank you all.
Oh and funny thing, these are two different ducks that appear to be the exact same cross, but they have been found separately at different locations.