Ridge of hair down a horse's back a breed trait?
I got a filly a couple months ago from an auction and we have noticed something unique about her coat. Starting at the withers all the way to where her tail bone starts there is a ridge of hair. At first we thought it might be bone and she just needed more fat, but when we felt it, it is not bone it is just hair that kind of sticks up more along that line (?) and won’t be smoothed down. What I was wondering is if this is a characteristic of a breed or maybe something else.
I tried to look around on google but didn't find anything helpful.
We know nothing about her breeding.