Trim excess fat from venison. In large bowl mix beer, garlic, salt, pepper, onions and bay leaves; add venison. (Marinade should cover meat) Marinate in refrigerator for 12 – 24 hours, turning occasionally. Remove venison and onions from marinade and place in slow cooker/Crock Pot. Pour 1 cup Barbecue Sauce over top. Cover and cook on LOW for 10 – 12 hours. Serve with remaining Barbecue Sauce. Serves 6.