If you hit him slowly he ll become smarter and faster so it s not a good idea. When he tries to bite you, you can kick him over the hoof which is very sensitive and also a blind spot or you can pick up your elbow so he will hit on it by himself. With these actions he will think "ohhh, when I try to bite I hurt and I don t know from where."
These methods may sound silly. My mare bites and one day she cut me off a piece of muscule from my arm. Luckily, she didn t cut the skin. After that, I searched a lot and found this methods and some more(I don t remember them) and believe me they have helped me a lot....
I hope they may help you too...
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