I will say this. I had a British male that in his hey day weighed 100#. Block head, short thick tail and a hell of a dog. I bought him a vest and only used it when temp were in 30s and below. Beau would have all exposed hairs with ice on the ends and not even shiver. Keeping the dogs somewhere to sit that is relatively dry is key IMO. Now, we never have the extreme conditions like other have, but -17 wind chill one hunt and he was happy as a dog could be. Damn, I miss him.