Gamey, as I definitely it in taste, is from 2 things.... adrenaline in the blood from deer that was hit and pushed before death and handling meat after touching hide.
I think those are two good reasons. But, hell, I don't even know exactly what "gamey" means other than an "off" flavor.
I'd add to those reasons 1) a bad flavor-inducing diet, like the onions. 2) gut shot on a scale from simply having the stomach broken to having the intestines broken to having the bladder punctured and 3) spoiled meat from being too warm for too long for whatever reason.
I don't think blood in the meat has much to do with it, at least not in my neck of the woods. The deer I shoot are agriculturally fed or eat acorns so they are pretty sweet. As it is, the deer lose so much blood from a lung shot, I don't think more is necessary. At least not for the deer I shoot.
You guys bleeding them on ice, I wonder how much the flavor is improved just from aging.
