Maybe when Strider died it was too much like tlk where he's killed by his own brother, who drives spirit off, but spirit comes back and defeats him and becomes leader
Spirit's dad was probably in the movie.They just did not say specificly who he was.The leader leads the herd right?well, think back to the beginning of the movie.The horse leading must have been Spirit's dad.
I don't think most people know why it could be alot of reasons, like Spirit's father had died because once Spirit had grown up he took full responsbility of the heard stright away.
His dad is never shown in the movie but hes a black horse so id say hes shown in pictures of black but yes he probally died of horse wranglers or something
Maybe because he's a horse, and they don'r take care of their foals like the mothers do? Geez, be a little realistic here. He banged Spirits mother, then moved on the the next.