My yorkie attacks my other yorkie while he's sleeping
 

I have 2 yorkies that are rather protective of my wife and me. One of these yorkies (Buster) is all talk. He barks at people in the hallway of our apartment building, on the street, and mostly in our apartment (but only when we're present). My other yorkie (Charlie) is more aggressive. In our apartment, he will actually bite people.

Both Buster and Charlie are little Napoleons when it comes to bigger dogs. Both will bark at bigger dogs. But, Charlie, unless restrained will actually go and attack the bigger dog.

Recently, Charlie has directed aggression towards Buster, his brother from another mother (they're from different litters). Buster can be laying on the couch sleeping with Charlie nearby, and Charlie may lunge at him unprovoked. What I've noticed is that this often happens when Buster is sleeping close to me or my wife so it may be a protective thing. Also, Charlie will attack Buster when he gets excited or anxious, such as when we are ready to go for a walk.

We've tried a little bit of training, which hasn't worked much. Also, we use a static collar and muzzle occassionally, which obviously prevents Charlie from doing any damage. But we don't want to leave this prophylactic measures on Charlie all day.

Does anybody have any suggestions? I'm not one for drugging my dogs (or my kids), but I feel I'm out of options. I want to be able to teach Charlie that he doesn't need to be so anxious and that he can mellow out.

Btw, Charlie is 5 years old, and Buster is 2.

Thanks for any insight anybody may have.

Best,
Josh

I have no advice as i am anxiously expecting the arrival of my very first yorkie. I searched for months until i found a local breeder. I started looking into shipping a puppy because of my budget and ended up hopping in a waiting list for a spring litter. I am saving to be able to pay in full from this local breeder and also do the pet insurance right away. I already have all the supplies. Anyways, from what i have found on my crazy road of research, some behaviors could be inherited and could that be the case of your dogs since they are half siblings? I met all the dogs from my breeder more than once and i am totally confident, by the way, i found her through a few referrals on this site and ironically also bumped into one of her yorkies and fell in love just to learn it came from the breeder i wanted to go visit. I have a deposit already in place and my yorkie will come home next spring. I learned so much reading in this forum, i hope you will get good advice and find a way to help your dogs.
Good luck.