Montana:
1. It is illegal to possess or transport the carcass of any big game animal unless evidence of the animal's sex and species remains naturally attached to it's carcass or a portion of the carcass.
2. Evidence of an animal's sex and species must remain naturally attached until the carcass:
-Is at the final place of storage; or
-Cut and wrapped in serving size; or
-Is at commercial meat processing facility; or
-Is at licensed taxidermist
3. If the head or antlers are removed, evidence of sex in the form of testicles, penis, scrotum, udder or vulva must remain naturally attached. For example, boned out or quartered animals need evidence of sex naturally attached to a portion of the meat.
Montana 2012 Deer, Elk and Antelope regulations page 11