The European Hares we had in South Western Ontario ran 10 to 12 pounds live (dead) weight. The odd one was larger yet. My Belgium Shepherd dog got them all. He loaded them. I'd chop them (frozen) in 1/2 with a sickle and he'd get 1/2 one day, and 1/2 the next.
The snowshoe hares out West here, run about 1/2 again heavier than a cottontail - maybe 2 1/2 pounds. Just a guess.
Just looked at the picture of the young man with the brace of hares. Our snowshoe hares are the same to just barely smaller than those but have longer hind legs & larger feet..