bahavior problems

Question
I have adopted a 10 year old gelding about one and a half years ago. Nugget was used to be with other horses, but since then had to be on his own due to my living situation. All has been going okay, apart from him being stubborn when it comes to lifting his hoofs for me. About 3 month ago he started to try to buck me off while riding him. He doesn't do that much anymore, but his behavior is still strange.
Today he bit me for the first time while standing next to him...I was just having a chat with him. All happened very fast and he stormed off as soon as it had happened. I chased after him for a moment and stopped him from coming back into the house padock, where he usually is fed, for the rest of the day. I am concerned about him. I know that he must be lonely and that my dogs and myself aren't satisfactory company in his eyes, even we live literally next door to his stable and he is part of daily life. I don't know whether getting another horse/pony is neccessarily the solution at the moment. Yet I understand that I need to help him somehow before behaviors like that would get worse and become a habit. He bit very hard and incapacitated my whole arm;... he meant it and was obviously very pissed of with me even I was feeding him at the time, which he always reacts joyful towards. I am wondering what I should do to teach him not to do such thing, and how to improve his mood. All I could think of was behaving like I thought a horse in a herd and of higher rank would respond. So I chased him away from the house area, where his open stable also is, and have ignored him since. I don't know whether this was the right thing to do; or what else I should do now. I am not scared but know that I should not tolerate him biting. I have never encouraged him to nipple on clothes or "play- bite".I don't know anymore whether it is lonliness, him testing his boundaries or whether he could be sick, even nothing seems apparent. If you have any advise for me and what I can do to improve Nuggets relationship with me, I would be delighted. I love Nugget very much and wish he would like me a bit better, too. Thank you very much! with kind regards, viola  

Answer
Dear Viola (lovely name- your parents must have been Shakespeare fans)
It could be quite possible that the lack of equine company has contributed to Nugget's behavior but it also appears as though he is rapidly losing respect for you as a human. He needs to know that you are NOT another horse and that you command respect. Many, many horses, including those who have previously had companionship do quite well alone. While you might try a companion or possibly just board him off and on at a place where he can have company- I would suggest that you still begin some behavior modification training.
Go back to some basics with him. Boredom often breeds contempt in horses and he needs to learn to respect you all over again. This doesn't mean that you aren't friendly or kind- but that he needs to earn your praise by treating you appropriately. Teach him that you have your space and he is not to intrude unless he is invited. Work him daily- as though he were a green horse. Keep a dressage length whip close at hand yet out of view. Timing can be everything. Keep your wits about you- he is clearly testing you. This time it was your arm- it could just have easily been your face or a child. If you don't have the time to dedicate to this- you might consider sending him out for a month or so as a re-school to a trainer who you know and respect.
You are wise to be concerned. Best wishes. I hope this is of some help.
Sincerely,
S. Evans