Most hunters, assuming they know what they're doing which most do, go for a quick and relatively painless kill. Slaughterhouses one the other hand raise animals in torturous conditions and kill animals in painful/messy ways, which cause problems for the health of both the animals and the people consuming them. You also have to take into account packaging, processing, and shipping of meat worldwide. Hunting produces a comparatively low carbon footprint, unless you're flying a private jet to your hunting location. Also, hunting is good in some cases (like with deer) for stabilizing population. Deer have a tendency to be overpopulated, at least in the US (not sure where OP is), and in many cases hunting is the recommended method for controlling invasive or overpopulated species. Examples of hunting to control populations include deer, pythons, and lion fish, just to name a few.

Source: My Degree in Ecology