Rituals (1977)

Five doctors go on vacation deep in the Canadian wilderness. After all but one pair of the party's shoes disappear, the remaining shoed camper decides to hike out and go look for help. Soon after he leaves, however, his four companions realizes that something is very wrong when someone leaves a decapitated deer head just outside their camp. Even though they still don't have their shoes, they decide to follow their friend's trail out of the woods, but their path is blocked by someone who doesn't want to see them leave the forest alive.