The vet has recently floated his teeth, wolf teeth have been removed. No apparent medical issues. His diet consists of sweet feed, a little hay, grass pastures, and amplify. He has access to salt and mineral blocks. He is in good weight, is exercised almost every day for at least an hour, and has pasture buddies.
As you can guess, it is the chewing on the reins that is the most annoying of the items. He doesn't usually try to put them in his mouth when I am riding, but feels the need to do it when I am leading him whether I leave the reins over his neck or pull them off his neck. I have tried popping him in the chest with my hand,growling, and then opening his mouth to take them out, but I feel like in the few seconds it takes between the pop and getting them out of his mouth, I have lost the punishment in translation.
Any ideas as to why he is doing this and how I can stop it? I am aware that there is bitter spray, but I would like to try that as a last resort because of the proximity of the reins to his mouth....unless someone with the same problem has used it successfully.
Thanks for any suggestions!