As a kid my old man raised Brittanies, mainly for quail hunting. But, being on the coast where it wasn't too cold he had a couple of them that were great duck dogs. I can remember Sam retrieving a "sailer" snow that went down a quarter mile away in the rice paddy. Took him 20 minutes, but he came back draggin' that goose backwards by the neck!
That being said, I have a 10 year old Brittany that has never wanted anything to do with dux. I've tried everything and it just isn't in her. She is great for upland... more or less what she is bred to do, but no go on the dux. I joke that she thinks she's too good for 'em.