you can do it anywhere, all 3d software
blender is just one example of the software which I like most for character rendering
so if you use/like blender, the software, you need it.
i'm saying this with the idea of hair as '3d mold'.
But if you are talking about another features to 'colorize/shade' the hair regardless the mold, then it's another thing that might be great to be added in game