Shih Tzu that bites

Growling and biting/nipping are the dogs way of telling you "I need more space", or "don't mess with me right now!".
We have a "Maggie" too, and she is also a bit of a worry with our GS...not that she's ever bit him, but if he gets into her face, she'll growl at him, and if he doesn't move, she'll do a quick yip/bark, to scare him away. We worry that if he doesn't move away, she will eventually nip him! So we constantly tell him to stay away from the dogs, when they growl! He's 3, so it doesn't always work:(
Teach the children to look for signs when Maggie is stressed or nervous, and giver her her space. Worst thing that anyone can do, is overwhelm the dog by trying to make her understand who or what they are.....such as when the neighbor picked her up (she had lost all control of the situation, and Maggie felt her only option was to nip the woman)

Being in a house with other dogs, Maggie probably understood the hierarchy, and while she may have been the smallest, that doesn't mean that she wasn't (or at least thought she was) the "Alpha" dog. Some just seem born to the throne!:)
If she was spoiled in the previous home, this only entitled her more. She needs to know who is the Boss....and people (all people) are the BOSS!!

We've got 8 dogs, who are for the most part very social, and well behaved, but as I had mentioned, Tugger is nervous around new people, and in his previous home, there was a lot of partying, and strange people in and out of the house, so he was trying to protect his home.....he started nipping at people. Of course, when that happened the first few times, people laughed (he's a small dog...no harm/no foal)...which only made things worse, as he seemed to think that this was accepted behavior. Eventually, he couldn't stay at that home, and we took him. 99% of the time, he's fine, and as I said, he's great with our 3 year old GS......is "velcro" to my DW, and is a great dog.....but, he's still nervous when strangers come into our house. The leash allows us to control him (we're not as quick as we used to be:)), and he's not bouncing around and aggressive when on the leash.
This works for us.....it may or may not work for your son, especially if there is a lot of traffic in the house on a daily basis.

How does Maggie behave when she is left alone....or allowed to mingle with new people on her own terms?? Small dogs (we've got Papillons) tend to get picked up a lot, whether they like it or not, so you Son and family need to be her advocate, and ask strangers not to do that....at least until she's ready!

It is often easy to think of these things in terms of ourselves.....how would you feel if someone strange were to pick you up? Nuff said:B

Good luck!

Thanks, PapPappy.

Rvten: A little history of the dog. According to the SPCA, the dog lived with a family who had children. They also had two bigger dogs who seemed to enjoy harrassing Maggie. Fearing they would injure her, they turned her over to the SPCA. According to the family, she does not have a history of biting.

We have a dog that will nip too. Tugger is the most gentle dog with our 3 year old Grandson, and the rest of the family, but he's not as nice with strangers.

What we do, is to keep him on a leash when people come over.....yes, it's a bit extreme, but he usually calms down after about 10 minutes.

Your neighbor was right, when she said that she was at fault....picking up a strange dog is asking for trouble....and then to place the dog in a position of submission (on it's back) is even worse.

I don't think I'd be to worried about Maggie....unless you see additional behaviors that indicate aggressiveness. You may want to have a dog therapist/trainer/behaviorist check her out too....it may be money well spent:)

Good luck

For one you do not know how the fog was treated by past owner.
Dog needs to get used to being handled by different people.
May take some work on your sons part.
Some dogs do not like everybody. Some people do not know how to approach a dog or handle one.