Adding a new dog

Question
I have 2 mini daschunds - both fixed females, 9 and 10 lbs.  I have a friend who found a local breeder who is closing due to her husbands illness. She has a puppy I like and I just wondered if my 4 and 3 y.o girls will adjust to a new baby.  My brother-in-law is a vet and claims this will form a "pack" and they will get rowdy (they can be rambunctious and torture their beanie babies, but do not chew, dig, or do any physical damage currently).  I give them tons of attention and could easily incorporate one more. I'd like another girl, is this OK or am I ruining a good thing?

Answer
Two dogs are a "pack"; whether or not they will accept another (especially a female) depends upon the temperament of all dogs.

You want to temperament test this puppy.  Sit on the floor while the puppy is in its original environment (surrounded by other dogs I would assume) and encourage the pup to come to you.  If she does so readily, without hesitation, put her in your lap for a few seconds, then turn her (GENTLY) over on her back (for a belly rub.)  If the puppy allows this without struggling, this combined with her willingness to approach you means she is bid-able to humans, secure but not overly so (not dominant.)  Assuming she passes this test, walk away from her and attempt to call her to you again.  Repeat the above.  If she does not come to you, avoids eye contact, goes in the other direction or otherwise ignores you AND/OR if she does not readily allow you to turn her over for a belly rub once she comes to you, you don't want to introduce her into your household.

What you are aiming for is a puppy that is social BUT will readily tolerate dominance by others, because your other females will probably establish immediate rank with her.  If this puppy demonstrates even the slightest bit of hesitancy, do not bring her home.

One rule of thumb: home grown breeders (those not breeding to type and temperament and without a long list of people waiting for pups -- the mini Doxie is NOT an easy dog to find) do not always represent themselves truthfully.  You don't really KNOW why this woman is dumping her stock.  Be sure this pup has had its initial vaccinations, is free of any sign of missing coat and has been wormed; STRONGLY insist you meet her dam (mother), siblings, and sire (father), if he is on the premises.  Ask whether or not this is a second breeding (meaning, another litter is on the ground and you can ask for references for their owners).  Ask if the breeder has done any genetic testing; ask if there are issues regarding cervical problems in her line.  Get a PEDIGREE you can look over before purchase.  Look at the names on the pedigree going back five generations (this is a standard pedigree form offered by legitimate breeders.)  Make NOTE if the same dam or sire used multiple times -- this is a line breeding and can cause all sorts of physical problems if the breeding stock has not been screened.

If the breeder has all the "right" answers and the pup passes your temperament evaluation, be sure the breeder has a CONTRACT which insures the health of this puppy against genetically inherited problems.  If you decide to make the purchase, take this puppy to your veterinarian BEFORE bringing her home; have a stool sample taken and let the vet give her a general overall exam to be sure there is no sign of illness or physical abnormality.

There's no reason you can't introduce another dog, albeit another female; however, you must be aware that YOU are the leader of this "pack" and you must insist that any behavior you do not want repeated can easily be controlled by your voice, alone.  Any further questions, please repost.