I know that humans can naturally have more than 1 hair color, whether that is in a transition from 1 color to another or they are born with it. Like for example there are babies with both red and brown hair at the same time. I myself have had both of these situations. I was born with salt and pepper hair but then it turned blonde and over 17 years it has become the medium brown it is now.
Now I know that this has to do with my fiction story but I want to know if there is a boundary as to how many natural hair colors a human can have at any given time. 2 colors is the boundary for eyes and 1 with lighter or darker spots is the boundary for skin but is there such a boundary for hair?
And even if there isn't a boundary how many hair colors should I use max? 3? 4? 2?