Not Dee but what you are referring to happened in Wyoming, not Texas. You claim to be a history buff so read up on that era in Wyoming. It wasn't all sunshine and roses.
I was not aware where the movie story was located since I didn't watch the movie itself. family disagreements perhaps (e.g. Hatfields & McCoys late 1800s). ...And we even have had some recent cattle thieves around here.
Of course, I don't rely on movies for much history, since they are admittedly mostly fiction.
But range wars in Wyoming? One would think survey boundaries would have been well set by then..
..But hey, it's worth checking up on..