yes but you will die
For a long as you like as long as the meat stays completely frozen. Some mammoth carcasses have been found that have been frozen for tens of thousands of years and the meat still exists.
Meat that has been frozen for years won't be good to eat any more. You should only keep food in the freezer for a few months for the best flavor.
20 years
Meat that has been placed into a freezer and left there until the temperature drops low enough to preserve the meat.
Ew no, you'll get sick...
Food which has been cooked can be frozen, even if it was frozen prior to cooking. BUT Frozen food which has been thawed, but not cooked, should never be re-frozen. Nor should food which was cooked, frozen and thawed.
It is not safe to consume frozen meat that has been left out for 12 hours. The meat may have reached unsafe temperatures and could be contaminated with harmful bacteria. It is best to discard it to avoid the risk of foodborne illness.
Frozen sheep meat
If the meat was frozen but now it isn't, I would call it thawed.
Not if the meat is frozen at 0°F.
in a meat freezer
Bacteria is found in almost any surface, including frozen poultry products such as chicken. Salmonella has been discovered to survive in frozen meat.