There is a certain difference in flavor of free-range meats. I think the biggest difference is that the muscles of the animal are used more and are, therefore, generally leaner. Another difference is that I believe the meat takes on a bit of flavor from what the animal eats while alive. If it is fed the same food over and over, it gets one flavor and if it is free-ranging, it eats a variety of things. However, that difference in flavor would probably be overwhelmed by the processing into beef jerky. My typical process is to marinate the meat for 12 hours or so and then dehydrate it. The marinating process will add way more flavor to the meat than the difference you might taste due to the diet while the animal was alive. I have also used dry rubs, but the end result is the same…the seasoning adds more flavor than just the beef. I guess if you wanted to see strictly if the diet made a difference, you could take some meat from each type of animal (free-range and grain fed) and just dry some of the meat without any seasoning. See for yourself if there is a difference.