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 to 24 hours, turning occasionally.
Remove venison and onions from marinade and place in crock pot.
Pour 1 cup barbecue sauce over top.
Cover and cook on low setting for 10 to 12 hours.
Serve with remaining barbecue Sauce.