I have had my new horse for a couple of months and he has now started to rear. I took him to a playday last week and he was fine the first part of the day and then started acting up. Pawing the ground, rearing and bucking a little. He acts fine when I am not on him. He follows me around the pasture wanting to be loved on. He is calm enough for my 8 year old niece to clean his hoofs but watch out if you try to ride him. One minute he will be so good and the next minute as soon as you try to get him to turn, the rodeo is on. I can not figure out how to stop this. I have tried to ride with a snaffle bit and a hackamore. Any ideas?