Even as smart as Border Collies are I think it would be harder than one might think. Transitioning a 1.5 year old dog from training dummies to real birds might be an issue. Retriever gun dogs are bred to have the instincts to retrieve and to hunt for birds Vs. herding. If you get past that hurdle I could see a BC retrieving a bird it sees on the water. I don't see a BC ever sniffing out a cripple hiding in the grass or finding a bird it can't see. I do like the idea of a non-traditional hunting dog working for you. Pull it off and you will be the talk of the town. I wonder what a professional trainer would think of the idea.

I hunt with Spaniels and I do use on use neoprene vest on the coldest days. I've only had one trip cut short from the weather being too cold. To be honest it was too cold for me as well. Protecting the dogs was a good excuse to go inside where it was warm.