Hey Cat Cat, I cook a lot of wild meats for my clientele on hunting ranches.
By law in the north west most wild meats are older male animals. Like turkeys most are over two years old (gotta have the longest beard biggest antlers), even a domestic bird that is old will be tougher than a say a two or three month old bird.
That being said what I use a lot when I can is an electric pressure cooker or a stove top PC. They will melt an elk roast or turkey to a moist soft yummy consistency (like pulled pork) The thing I like about the electric pressure cooker is that you set it and forget it.
Hope that helps.