Those are definitely both drakes, beyond a shadow of doubt! They are either Snowy Mallards (my guess) or possibly Mini Appleyards. I have had Appleyards that have looked almost identical to Snowy Mallards.
The egg has to be coming from one of your chickens.
Also, what muscovy said is true, sometimes a drake can look like a duck (sometimes permanently so, rarely though). This seems to happen from time to time with males of some species. I have never ever seen the reverse, a duck look like a drake. I am sure it might be possible, but it would have to be very unusual.
i guess i'll have to wait and see if they hatch to solve the mystery. would the white chicken lay pinkish tan eggs? i thought leg horns and RIW laid white eggs that where large?
I do! It is fascinating. I would love to know. I already tried to find something out from google and didn't see anything. Oh well, I should be doing homework anyway. LOL