I think Donavan and Steve got into a fight about how Donavan treats his animals. Steve is a guy who loves horses and doesn’t ever want to see one get abused. But just that, Donavan was abusing one of his horses and Steve didn’t like that, he decided to pay a little about for it and take care of it on his own. Before Donavan agreed to that he fought Steve. I also think Steve turned Donavan and Romero in for drug use and then ran away because he was wanted by the police too. So if he turned the boys in, they would do the exact thing and turn Steve in for revenge.