But he has reverted horribly! You can't catch him anymore, he takes off running and bucking.
Then something you're doing with him is causing him not to want to come play your games. Analyse what it is you're doing wrong & what he thinks of it all.
He's picking on my TW gelding now too. Which he never did before. Considering my TW is soo much bigger than him. And dominate at that. I'm not sure whats going on with him. We've had him for probably about two months.
Without knowing specifics, don't know whether he is actually being a 'bully' but what's more likely IME is that he's got to know your boy & gain confidence with him to play with him. Also if they're both 'dominant' types, that means more 'boy games' likely
And now out of the blue he's acting out. IF you can catch him he is usually okay, but he's been spooking easily, and when he's under the saddle he's being jumpy too. He has been rode frequently since we've had him.
Horses generally put up with an awful lot if they don't believe they have a choice, and young green horses are often spooky, as they don't generalise well & not solid on much, so it may not take anything big to cause a horse to 'blow up out of the blue' - but there's always something, just that we may not notice what.
But as he's only 4yo & you've been doing lots of riding & his behaviour has suddenly changed, I'd say pain is a fair bet. As his body is still immature his back & joints are easily damaged from weightbearing. He will also be changing shape so if ridden in a saddle, it needs to be evaluated very often to ensure it's still comfortable for him.
I bought vitacalm hoping it would help him. If not I'm going to have to send him down the rode. Please keep in mind I'm pretty experienced with horses, and I've done about all I know to fix him.
Magnesium is a very important mineral which is commonly deficient/imbalanced in the diet. It is also associated with behaviour & more is needed when the horse is stressed. Whatever feed he's on may also have a bearing on his behaviour too.
Sending him 'down the road' I presume is to a trainer? Of course the more good training a horse has, the better, but I'm afraid that from what you've said, it sounds like something about whatever you & your husband are doing(can't tell because you provide no specifics) is causing or exacerbating the problems, so I think it's probably a good move if you all 'go down the road' for some training together.
Me and my husband both have done TONS of ground work with him.
Has he enjoyed this? Has he been keen & willing? I personally think it's important to teach/play with them in such a way that they enjoy their 'work'. If that's not important to you, then of course he's not going to WANT to come to you, so you've then got to ensure that ignoring/running away from you is punished effectively enough that he sees work as 'the lesser evil'.
I've even had several friends who own/break horses come look at him and ride him. And as soon as they get on him he's fine. Doesn't offer to do a thing. I don't ride this horse what so ever. He doesn't like me on his back.
So he's not 'fine' with your husband? Then it's likely - pain aside - that it is you & your husband that need more training, as much or more so than the horse. Especially you, if you can't ride him at all.
So... all in all, respectfully, it just sounds like you're not very experienced & this horse isn't either - he's not a beginners type horse & you could all benefit from more experienced... partners.