Cayuga ducks?!

[Animol]

I just got two cayuga ducks from a friend as he is moving to africa and I have a few questions.
Are they both male, a pair or both girls? 1 is almost half the size of the other and has a crooked beak and otherwise seems just fine and is completly black. The larger of the two has been mounting the smaller but I read somewhere that onle females have white feathers and 'he' has one white feather so have I got a lesbian duck? It has the curled feather tips on it's tail so I'm guessing male? The smaller doesn't and their the same age so have I got a pair?
Do they have any special diatary needs, I keep chickens and the guy said I could just give them layers pellets.
What kind of treats do they like?
Anything else I need to know?

 

[Amiga]

See if the Stickies help with some of your questions.

Sounds like you have a drake/duck pair. We would love to see photo's!

https://www.backyardchickens.com/t/256233/ducks-sticky-topics-index

Interesting that one is half the size of the other. I don't see such size difference in my Buffs. Please tell us more!

 

[Animol]

I think it's probably because she didn't get much to eat because the top part of her beak is twisted to the side. Filled up their kiddys pool today and they made it muddy in like, three seconds. They are funny! At the moment they aren't very human friendly and run away when I come near but I plan to change that

 

[Amiga]

Muddy pool is healthy duck behavior! Great!

Most of my ducks like thawed frozen peas for treats. The three new ones really liked autumn olive fruits, which grew where they lived. I am introducing them to peas, and have been offering blueberries since they seem to prefer fruits to veg. Everyone likes leafy things like dandelion, chickweed and lettuce. A few like tender collards and kale.