I have boarded my Horses with a stable one time where the owner was a loooong time Horse guy.
But he had old style thought of how to treat Horses my Horse at the time didn't like men at all I told the owner that because I was going to do the feeding and cleaning of the stall.
But I came in there twice while he was in with my Horse I asked him why he said he was going to turn my Horse around for me he didn't like a horse that got to make the choice of who was in the stall with him.
I took him out that day because I was fortunate enough to have had found another place for him.
But my Horse did take something away from that stable a bigger hate for men.
And since my Horse was a Percheron Clydesdale cross when he got upset you had to watch out.
IF you want to continue training your youngster get him the heck out of that barn there is never a reason for a barn owner or anyone puting there hands on your horse is a mean way it takes away from all you are doing to train thunder. I have been a B.O. AND Manager of a barn and we would never stand for that to happen. A person who can not handle your horse with out abuseing it should not be running a boarding stable any time any where . You said you didnt like running in to the BO think what thunder is thinking when he is stuck there all the time with this waste of a person . MOVE THUNDER ASAP