A horse can be not scared of people but not trained yet in how to behave properly. It sounds like he is still nervous which can only get better with more training
I used pop rocks for months when my horse was having ulcer issues. His ulcers ended up being related to a previously undiagnosed osteoarthritis issue, but nonetheless, the pop rocks had zero effect on his gut. While on pop rocks he was scoped and was found with grade 3 ulcers.
If you really think he has ulcers, get him scoped. But I wouldnt waste my money on the pop rocks.
