I bought a nice meat grinder last year right after deer season. I'm looking forward to making some sausage this year. I have made several batches with pork shoulder and it does not have enough fat by itself and it sure isn't going to if I add deer meat.

What do I ask for at the butcher?

Beef suit. That's what I use. It's the fat trimmed off steaks and roasts. It's just perfect to grind along with your hamburger. I've used unsliced bacon for sausage along with just adding sausage that's already ground also.

Pork trimmings also. Whether you use that or beef fat is just a matter of personal preference.

Don't have a cooperative butcher nearby? You can use a package of bacon, salt pork, or "bacon ends and pieces" from the grocery store. That will add a little salt, FYI.

Good luck.