I would also like to add that the changed stabling, with OTHER horses, is going to make a BIG difference in his reactions and carrying on vocally. He has gone from an "only horse" to being in a herd, has attached himself emotionally to the mares. I see this often, at Trail rides, and it is hard to deal with.
I agree that the attempts to put tack on could be the handling, not what horse is used to. Could also be that horse KNOWS he will be leaving "his herd girls" when saddled and gets quite anxious about it, to the point of being uncooperative. Doesn't matter how he was at home, in new place things are different, and he will react differently to them. He is probably herd bound at this point, may take more of an experienced handler than OP is to manage the problem.
A suggestion would be to use a mechanical hackamore so he doesn't need to open mouth, see how he rides off for you then. Be prepared for some bouncing around if he is really resistant to the idea of leaving.
A truly proud-cut horse can be determined with a test by the Vet for testosterone, as would be produced by a retained testicle. Horse would probably be much more stallion-like, endeavoring to breed the mares, if he had a retained testicle. Such a problem can cause cancers in the horse, probably would need surgery to remove in a clinic setting.
From the written material, sounds like horse is trying to fit in, but confused and really attached to the mares after his previous life alone. Changed handling has added to the problem, he is confused and resistant to the new folks desires. The very stocky built animals, short neck, easy keeper types are often called proud-cut when they are just carrying too much weight.
I agree that the attempts to put tack on could be the handling, not what horse is used to. Could also be that horse KNOWS he will be leaving "his herd girls" when saddled and gets quite anxious about it, to the point of being uncooperative. Doesn't matter how he was at home, in new place things are different, and he will react differently to them. He is probably herd bound at this point, may take more of an experienced handler than OP is to manage the problem.
A suggestion would be to use a mechanical hackamore so he doesn't need to open mouth, see how he rides off for you then. Be prepared for some bouncing around if he is really resistant to the idea of leaving.
A truly proud-cut horse can be determined with a test by the Vet for testosterone, as would be produced by a retained testicle. Horse would probably be much more stallion-like, endeavoring to breed the mares, if he had a retained testicle. Such a problem can cause cancers in the horse, probably would need surgery to remove in a clinic setting.
From the written material, sounds like horse is trying to fit in, but confused and really attached to the mares after his previous life alone. Changed handling has added to the problem, he is confused and resistant to the new folks desires. The very stocky built animals, short neck, easy keeper types are often called proud-cut when they are just carrying too much weight.