When I first started cooking, I had no idea what a bird tenderloin was, let alone where to find it. Then I thought it was along the back—but every big game hunter knows that’s where you find the loin, not the tenderloin. But after several years of butchering birds, I have come to believe that not only is a bird’s tenderloin very easy to locate and remove, but it’s something worth doing every time you breast out a bird.