Fighting between two female Shih Tzus

Question
Hello Erica,   I have three Shih Tzu's that are having trouble getting along.   I have a 5 year old neutered male and 3 year old spayed female that get along great.  Never had a cross word between them.  We added a third dog nine months ago.  A female who is now 14 months and spayed. The youngest is very demanding, wants to be held all of the time etc.  Until about a month ago, despite the young pup's demanding ways, all three dogs got along okay.  Now the two older dogs are fighting with the younger dog.  The younger dog has started marking me and her toys.  She is also humping the 3 year old female.  During one of their fights, blood was drawn.   My vet feels we should find the younger dog a new home where she is the only dog.  Do you agree with his assessment or should I continue working with the dogs so they can live together.

Thank you,  Leslie

Answer
I do not feel rehoming the younger dog is the first option.  It sounds like as she is reaching maturity, there is some vying for top dog position in the home.  That is very normal.  She is more than likely a very dominant female, and trying to tell the other dogs-and you-that she is now in charge.  I would strongly recommend you enroll in a local obedience class.  This will help you re-establish yourself as being the one in charge.  I have also added some links that should help:
http://www.jumpinjacs.com/home/leader_role.htm
http://www.jumpinjacs.com/home/gaining_attention.htm
http://www.jumpinjacs.com/home/class%20handouts/Master%20the%20walk.htm