Kc only fly for a year and sometimes when you mix different duck breeds they don't get along. I have all khakis and I have never had a problem. And the reason its butt is crooked might be because its developing an egg.
I would do khaki Campbell's for sure. They're a small breed duck only 4 pounds, best egg laying duck, and they're not mean veerrryyyy cccuuuttteee and you don't have to have a large quantity of them. They also love the water.