my new dog doesnt get along with the other two dogs

Question
Recently, I found a small white female terrier in my neighborhood.  She had a collar, but no tag, and my family's done everything possible to try to locate an owner.  If we are unable to do so, we have decided to keep her.  The problem is, our two female shihtzus (Abbey, 11 yrs and Emmy, 9 yrs) do not seem to like her and have responded negatively to her since she's been with us.  They growl whenever I am giving her attention and have become withdrawn, less playful with us.  We're worried that this new dog will continue to affect Abbey and Emmy, and that they will become unfriendly and resentful of us.  As far as I've seen, the new dog doesn't do anything to prompt agression from them - in fact, she is very submissive with them and tries to stay away from them.  At first, she tried to play with them but they snapped at her.  Emmy is particularly vicious, and Abbey has gotten sulky.  

If you have any adivce at all, I'd be very grateful.  We have to decide whether or not it's a good idea to keep this new dog with us or put her up for adoption, if we cannot locate the owner.  Thank you for time and consideration!

Anne

Answer
This could be difficult.  Your dogs are old enough to be set in their ways and not ready to have their routines upset.  If they are settling down to ignoring her and not showing aggression, perhaps go ahead and keep her.

Long term, it might be better if you provided strong leadership.  The key to most behavior problems is approaching things using the dog's natural instincts.  Dogs see all the people and dogs in the household as a pack with each having their own rank in the pack and a top dog.  Life is much easier if the 2 legged pack members outrank the 4 legged ones.  You can learn to play the role of top dog by reading some books or going to a good obedience class. A good obedience class or book is about you being top dog, not about rewarding standard commands with a treat. Start at http://www.dogsbestfriend.com/  For more on being top dog, see http://www.dogbreedinfo.com./topdogrules.htm