I have heard of a few things to put on your fresh-kill meat when in the field to protect it from flies and other bugs. Some recommend, for example, that you pepper the meat extensively. But I have just the thing to use so that not a single bug will even land on your meat: saturate it with Wesson Oil. Next time you're out hunting, bring along a gallon of Wesson and a rag. When you are dressing your game out to hang or carry back to town, saturate the rag and dab it all over the meat. You can even fill your chain saw with nothing but Wesson Oil to quarter your meat. That way, you won't have to worry about cutting away the usual chain saw oil later on.
Wesson Oil will make the outer layer of your meat look a little dark, but if that bothers you, you can always cut it away. So leave your pepper, salt or any other remedies at home and instead take along some Wesson Oil.