I quit hunting iced up areas after a similar experience. I knocked a bird down in a partially iced up river and my dog couldn't get back up the ice. He was swept downstream about 100 yards before a bend in the river allowed an easy place for him to get out. I dropped my shotgun and tried coaxing him every step of those 100 yards.
Since that day if there's ice, I go hunt pheasants or something else. He had a vest on too. Not sure if it saved him or not.
