It sounds like this guy is either in pain, or like mentioned above has learned to dislike humans. Due to this, he is probably very anxious and antsy. I had a horse like this, and what worked for him was, as mentioned above, earning his respect and trust. For two weeks, I would go out to the paddock, give him a good rub, yeild a few areas, give another rub, then leave him alone. My the end of the two weeks, he was walking to meet me in the paddock with ears forward. I used gentle persistence, but was firm in what I wanted and didn't stop until I got it. After two weeks, I started taking him out of the paddock, another good rub all over, quick yeilding session, more rubbing, then back in the paddock. It took a month of doing this until he became eager to work, and in a very relaxed manner. He is now a wonderful horse who loves people and is no longer disrespectful or anxious. I think what this guy might need is a reason to trust, and respect people.
Posted via Mobile Device