My dog is always hungry! She is a toy chihuahua. She will eat her food. Then if I don't pick up my other dogs food she will eat it too! Then she will throw up all day. We have also noticed that she will eat her vomit and we also caught her eating her poop! But when you look at her she looks really skinny like she never eats. I have been trying to feed her a couple of times a day so that she won't be so hungry but she still looks starved! Please help.
That poor baby needs to see a vet ASAP. She likely has a severe infestation of intestinal parasites, but you can't know for sure what type or even if that is her only problem without the vet running some tests. DO NOT GIVE HER ANY OTC WORMER LIKE HARTZ OR SARGENT'S!! These should be taken off the store shelves IMO, as they often cause more problems than they help, particularly in puppies.
Please get her to a vet and post back when you find out what her problem is and how she is doing.