[FirstYorkie]

Do they draw blood when they fight?

The obvious answer is to separate them for feeding and when they have toys or treats. If the fights are serious enough to draw blood, then I wouldn't leave toys laying around for them when they aren't either separated or closely supervised.

When you walk in the door, put them in a sit-stay. That way, they can't fight over who greets you first.

One exercise that I have read is good for reducing aggression between "siblings" is to get some treats and have them both sit in front of you. You then dole out the treats - one for spot, one for snoopy, one for spot, etc as long as both boys are sitting and waiting their turn. If someone won't wait their turn, make him sit back down. He doesn't get his until he is showing some self-restraint.

If they draw blood when they fight, it would be a good idea to consult a trainer.