I don't use any.Fat is the first thing that t urns rancid in the freezer. Use a little olive oil when cooking
This with my wild game- musk ox excluded when I can get it gifted to me. That has enough natural fat in it. And it doesn't make the freezer anyway in the amounts I've gotten.
I have always found it ironic that the butchers charge for a waste product added to perfectly good game meat.