[Kiwibaehr]

I am thinking you may have a very serious situation on your hands. I would immediately start separating the 2 boys if you have a way to do that. Yorkshire terriers are cute dogs but they do have the instinct to kill - they were bred as vermin hunters and they still have that genetic instinct. I would be very concerned that the 2 boys could get into a fight. When they do that, the one with the larger head will lock onto the one with the smaller head and won't let go - trying to kill the other one. I am sorry to be so forthright but feel as though it needs to be said. You may need to rehome one in order to avoid this. I am so sorry you are going through this but you need to protect them both. Best of luck