Yes the behavior is treatable with alot of work, others here will give you great advice. God Bless you for opening up your heart & home to this poor dog, I hope you can work with her and give her what she needs, poor little thing has never known love or security.
Christine

She needs obedience training & lots of patience.

If you're overwhelmed at the prospect, as well you might be in your situation, see if you can find a new home for her with someone you know, or try to find a Shih Tzu rescue that has a tax exemption so that you *know* it's a true rescue & not a front to obtain purebred dogs.

Whatever you do, don't let go of her until she's been spayed, & don't advertise her on craigslist.

Puppy mills & backyard breeders aren't going to tell you that they're puppy mills & backyard breeders;
they know exactly what to say & how to say it to get what they want, which is a dog they can put back into a cage & breed until her uterus falls out.

I wish you the best.

QUOTE>I did some online research of her background and it appears that she came from a puppy mill breeder, then to a pet broker, then to the pet store where they bought her. She was born on June 30, 2008 and they bought her on October 19, 2008, which means she was confined to a cage for 4 months, which would explain her strange behavior.QUOTE

Other than looking at a pedigree I didn't know you could even do any kind of background research on a dog. It's just amazing how much stuff is open for viewing.

Aren't Shih Tzu's bred to be lap dogs? That may be why she is very much into wanting your attention. I would also suspect she is still nervous about being left (again) in a new environment. She is still a young dog so just some good old fashioned walking will probably help with her energy levels. Also walking when she normally goes poop will help with her bowel movement. And since she is such a small dog you will probably notice a difference in just walking her around the block.

As far as pooping in the house, I would restrict her and basically go back to house training rules. Is she pooping in just one area? If so, you need to get a odor neutralizer. If there is a hint, and you won't be able to detect the smell, the dog will return to the area.

One of my dog's new friend is a Shih Tzu. She is an adorable little dog, kind of feisty, with a mop of hair. She's under a year and like any pup, she is full of energy.

I don't know if this is true of dogs, but with cats the accrediting association can tell you how many registrations a breeder does per year. In my case, my (now departed) Persian was from a "breeder" with many, many registrations. Definitely a "mill".

welcome to the wonderful world of the shih tzu. we had one little guy "Buddy"that was so mean, he bit and growled all the time if you said to him hows your little foots, he would just come after you! i think he might have come from a puppy mill. the house where we got him from was really weird, wall to wall stuff and the "babies" were in a play pen, plus i noticed in the paper that this woman had ads in the paper for puppies every 5 months or so.(he also peed all over the house and the sofa, he would just dare you to say something while he was doing his thing. sad thing was buddy passed away 1 week before his 9th birthday. one year later "Gracie Joy Devine " came into our lives, she was a gift from by husband for my birthday--the big 50, i went and looked at these little girls (1lb. 14 oz) she picked me and we have been friends ever since, my dear,dear love of my life passed away 3 weeks after she came home to live with us, she will be 4 on dec. 2, she goes on pittle paper, you should also know that shih tzu are the hardest to train and they also eat their b.m.'s. they do not like to be alone and this might be the way they are punishing you. our Gracie is 7 pounds, wears puppy clothes and loves to ride in her puppy stroller, yes i am weird, i have never heard her growl at all so you can see how different they are Gracie is just happy to be happy, except for this week she has to wear her puppsters because she is in heat (these can also be used for those little friends that are hard to train. even though these 2 were as different as night and day, they are just lovable little friends!

I guess nobody told you about a Shih Tzu personality BEFORE you took him in?
They are very smart, happy little dogs with a HUGE personality. They talk with their eyes.

Having been a Shih Tzu owner most of my life, I can tell you that they are one of the best dogs....BUT they train you, not the other way around.
You are lucky to cater to them ;)

These dogs are very sensitive, and take things in when you least expect it. They are more like people, or spoiled brats. LOL. They are not yappy, or hyper dogs, unless they were damaged...as in having irresponsible breeders or owners who didn't care or didn't understand their personality.

Their personalities are closer to medium dogs...and PEOPLE. They manipulate you, and they come first. You need to have a routine and boundaries with them. They will not listen or go away like most dogs. They'll argue with you. Just wait and see. They need positive reinforcement, and lots of praise. Never scold them. They have to get things THIER WAY, or they will pout, be unhappy, and possibly get into trouble... I know I'm biased but they make the BEST pets. Once you learn that your Shih Tzu is the boss, you'll get along just fine. LOL.

They are a lot of work grooming-wise....and sometimes not the best pet for the much older peeps.

Cleanliness is a must with these dogs:
1- You must have their ears plucked every couple of months. You should use an ear washing/drying solution i.e. Nolvasan, once every 1-2 weeks to keep their ears clean and DRY, so they don't get infections. Ask a Vet Tech how to use it. The hair that grows in the ears keeps the ears moist, so the bacteria multiplies and festers, and they can get infections. That goes for all the long haired dogs.
2-You must keep the eye area trimmed, clean and wiped, so they don't get eye irritations/infections. Many Shih Tzus lose their eyesight early in life because their owners don't take care of their eyes properly.
3-They need to be bathed 1-2x a month, with constant MOUTH wiping. Keep a hand towel, or tissues handy. I wash my Shih Tzu's mouth a few times a week, additionally to wiping and bathing. Just a quick rinse and wipe will do. The food sticks to the long hair, and they start smelling....THIS is very important. I wipe my dogs' paws after going outside, and wash her paws after walks. The long hair really picks up a lot of dirt and dust, which spreads to the rest of their fur and the house.
4-They have hair growing out of every hole in the body, so constant trimming is necessary i.e the butt area, eyes, mouth, paws, and ear plucking.
If you follow these suggestions, you will avoid many Vet visits.

The great part is that although they require a lot of wiping and some washing, they don't shed.

A clean Shih Tzu is a happy and healthy Shih Tzu.

The running around is extra energy and will subside if you walk him, and/or when he grows out of the puppy stage.
They are easy to train, but consistency, praise, and persistence are necessary.

If your pooch poops or pees in the house....say NO! in an authoritative way (not yelling) and immediately take him outside, and tell him- GO HERE!(obviously he won't go at that time cuz he just went in the house)so then take him back in, saying nothing. Just leave him alone and walk away....

I would take him out often in the the first year. You may want to utilize hanging the bell at the door, or near the door routine. Ring the bell, open door and go pee outside... When he goes, get all excited and tell him GOOD BOY! and give him a treat. They really want to please you. Good luck.

Leash walks leash walks leash walks....anytime you get 15 to 20 minutes, take the dog for a leash walk.
Also, since your dog is already interested in you, utilize that to your advantage..teach your dog some tricks. They are not hard to complete. Sit stay lay down, roll over....good luck

Lots of outdoor exercise. This is a young dog who requires an outlet for her natural energy. Most likely she is not getting the exercise she needs.

Frequent outdoor excursions allowing her the opportunity to relieve herself outside and lots of praise when she does. Help her to succeed at house training by being vigilent and taking her outdoors at the slightest sign of restlessness.

Her behavior does not sound strange but pretty much typical of a young energetic dog, confused and perhaps stressed by a new environment. In short, a new young dog requires a lot of work just as a small child does. It is the nature of the beast. If you cannot be a caregiver this is probably not the best situation for you or your new young dog.