He may just be thrown out by the change of you having him, they tend to take a while to take to you and apparently it's usually a year befre they fully attach to you. When he is presenting aggressive behaviour, whether it's a near bite or he's putting his ears back, turn a blind eye to it. The most important thing to them is your attention, and so he'll see this as a negative. Carry on as you would without the aggressive behavious and it should start to simmer down. If not, you could always try researching his background and temperament of the mare and sire he was form, their temperaments. The brood mare may be more important than the sire, but apparently as humans do, they imitat the behaviour of whoever is around.

It may be worth it looking up his owners and maybe getting in touch with them, and getting to know their theories of treating a horse, he may have experienced some form of aggression towards him in earlier years and may still be unsure, so is presenting it to you.

There's also the factor of him testing you, as all do. he wants to know what you'll accept and turn a blind eye to and what you think is absolutely unacceptable. In time, he may calm down, but if i were in your position no matter how hard it is at first, ignore it and him until he returns back to his normal way of behaving.

:) Xx

We've all got different theories and opinions, and these are mine, something different may work for you.

Pride is "grumpy" when i feed him in his stable. He pulls faces but that's about it. I have had him 4 years and hasnt changed. But if i feed him outside he is fine. I think it is a settling down time for your horse. You need to get used to his ways and he needs to get used to the way you do things. He may be moody about his stable, as he may think that is "his space". Have you tried putting his feed in and leaving him alone with it and i mean not even leaning over the stable door, just watching from a distance? Good luck. x