Q. 2yr old unfixed male Swiss Mtn dog Started a new behavior of barking loudly in my face. No does not work. He does this if I go to the barn what's up
A. Fear barking should be treated delicately. You should use high value treats (chicken, cheese sticks, hotdog bits, diced ham, cooked fish, turkey pepperoni, turkey bacon - all cut into tiny little bits.. or peanut butter in a squeeze tube, etc) and with the high value treats you should begin feeding them as soon as your dog becomes uncomfortable. Try keeping your dog under threshold. If going to the bark makes your dog bark (out of fear of the barn), then slowly work on his attention just outside of where he would bark. Slowly move closer feeding him treats the entire way. If at any point he begins barking, back up and work under threshold.
If this is separation anxiety, you should be working slowly at leaving your dog behind. First, make it seem like you're leaving, "coat/shoes/keys/hat" and open the door, but close the door and don't leave. Toss your dog a few treats without looking at him or talking to him. Slowly work on exiting for short amounts of time, returning to toss treats
A. I would need more details about the barking behavior. This could be "learned barking" which is essentially your dog learning that barking has gotten him what he wants in the past, and he is using it to get what he wants. This could be "attention barking" which is your dog barking to gain your attention. This could be "fear barking" which is coupled with being skittish, jumpy, tucked tail, whale eyes, excessive panting. If it is fear barking, you'll want to find the source of your dogs fear. It could be "separation anxiety" which can lead to your pup barking excessively.
If it is learned barking or attention barking, you have to show your dog that barking does not get him what he wants. Ignore him each time he barks. Occasionally this will result in him trying HARDER to get your attention through louder, more intense barking. This definitely needs to be ignored or you dog will learn "oh barking HARDER get your attention!" If this is fear or separation anxiety, you should be careful.
A. It can be a couple of things. It can be a dominance issue or something in the barn might have spooked him in the barn and he feels the need to protect you from whatever it was.