One of my two feed store call mixbreeds. Brownie is probably a khaki campbell/white call duck mix that is mallard sized. Or at least i'm 95 percent sure. Quite friendly but also a little shy...
No, I bought him fron a local feed store when he was half feathered out as a duckling. Yeah, there's no way he could be a call x mallard or call x runner because 1. He has orange feet 2. He has faint green color on his head. 3. He looks nothing like a mallard. That's why I have to agree with you that he is a white call x khaki campbell.