Sanity check--- Duck or Chicken??

This is really going to sound strange. And I will start from the beginning..
Late last Summer we, (the farm) were given 2 young call ducks. One white and one standard mallard colors. We've always had free range chickens, we have a good size pond, barn, horses, dogs and cats. So I thought, why not take the ducks.
At first they pretty much stayed in one of the horse stalls (with out the horse) and very often some of the chicks and roosters would go in and chat with them, share some food and water. Eventually we allowed the ducks to go free range, and they winter well. This spring, I noticed that the standard mallard was most definetely a he, while the white one was a lady. She laids eggs which we actually hatched in a incubator.
Anyway she went missing about 3 weeks ago. I thought, maybe she's sitting on eggs, I figured she'd come out of hiding soon. Unfortunately that wasn't the case, and we have not seen her since.
Our boy on the other hand has been having a good old time with some of the smaller hens. (bantam size). At first I thought he was just nipping/playing with them, but he is actually climbing on her.....
Last night I went to put away some tack in the barn and he is now roosting with the chicks up on the rafters. Identity crisis??
Has anyone had a duck that has done this before? I just got a couple of pekin's that are only 6 weeks old. They are just getting use to being outside. Do you think he'll recognize his own species and start hanging more with them?
Sorry for the long and detailed story...
Thanks for listening and if anyone has any advice please let me know.

Pat

 

Thanks, I'm glad that Quack isn't the only male who 'likes' chicks.