5 year old chihuahua having behavior problems all of sudden

Question
I have a 5 year old chihuahua who up until recently has been a very well behaved dog. However over the past couple of months, her behavior has changed. She snaps at strangers when they come inside the house, even biting at their ankles usually only when they turn their backs on her and start walking away from her. She also has started to go poop inside her crate which she has never done. Now I attribute these problems to recent changes in my own life. I had a baby 8 months ago and have not been paying as much as attention to the chihuahua as I should. Her normal walking and playing routine has not been the same since baby. Also we recently just moved into a new house. She also has had to deal with a lot of strangers coming to the house such as painters, new babysitters and such. I know this is a lot for her to deal with. I know I need to get her routine back to normal. What else can I do to try to alleviate these problems? Also am also worried about chihuahua growling, snapping, maybe even biting at baby who has recently started crawling and of course wants to go after the dog. Any help would be appreciated.

Answer
Have the vet check her.  The problem likely is the changes in the household, but you can't train a physical problem away.  Many dogs don't adjust top changes very well.  Perhaps you have failed to give her the leadership she needs.  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