Anyone looking to stir fry ANY meat, not just game meat, here are a few tips.
Make sure that each piece is similar in size.
Soak the meat in cold water, and agitate it for about 5 minutes. The water will turn pink, that is what you want. that pinkish hue is from the myoglobin in the meat. That is what leaks out of your meat when you are cooking it. It is not juice, or blood, but a protein. By soaking the meat, and working it a bit, this gets rid of it, and ensures that it will brown up rather nicely. Drain the meat, and pat dry with paper towels.
Season the meat some, I usually use ground black or white pepper, some garlic or onion powder, and a few splashes of soy sauce or tamari (if you are celiac, like my daughter). Mix, and add a few Tbs. of cornstarch or tapioca starch, and mix again.
Let it marinate for anywhere from 1/2 hour to overnight.
When ready to stir fry, add a few Tbs. of oil, I use avocado oil, it has a high smoking point (around 500), and is NOT an inflammatory seed oil. Mix well, so each piece is coated.
This process is called velveting, and is how Chinese stir fries are prepared. The meat is tender, juicy, and flavorful. But it can used for any type of cuisine. Think marsala.
Stir fry in batches and don't over crowd the pan.
Keep vegetables uniform in size, and pre cook them.
Make the sauce last in the pan, to get all of the brown bits, or fond, from the bottom.
hope this helps, enjoy.