normal? she's mixed chihuaha and maybe terrier

That's probably okay for that breed. The ribs shouldn't be REALLY visible, but you should be able to feel them easily. Wouldn't hurt to put a little meat on, but don't go overboard. A little underweight is better than overweight with dogs.

It is my understanding that you deturmine the healthy weight of a dog by being able to feel the last two ribs. Wither you should be able to see these or not varies by breed. Since you have a mix it is harder to tell, but if you can see ALL her ribs in detail, sounds like shes underweight. If you are feeding her properly, and you can just sort of see her ribs or if you can only see a few, then shes is probably fine. I wouldn't be concerned unless she is either not eatting her food, vomiting, or showing other symptoms of being sick (like sleeping alot).

You need to put your dog on a serious weight gain plan. Iams will help your dog gain weight.

look to her nutrition is she getting the proper feedings? and how old is she? if she is eating alot and still does not gain weight she could have a parasite have your vet do a stool sample to check.

NO - it happens when they age, get worms, have teeth/gum issues and mouth hurts to chew, get a distended stomach, or have a disease like cancer, you need to take her to a vet. Does she have appetite and eat/ Drink a lot of water? Show blood in her stool or urine? Have pain in the usual lymph node locations (under jaw, armpits, groin, abdomen area?) You'll know if it's tender if she growls, bares teeth, tries to bite, etc. Is her nose wet? Breathing hard/abnormally?

No.. feed her a little more if you could see the ribs.

Got to the pet store and buy some worm med. It's like $5. Just split the dosage on the back if it dosen't have your dog's weight. It won't hurt. You should do this regularly. If that don't put some weight on her, wait about a week, take her to the vet! GOOD LUCK!!