I'm having a similar problem
http://www.pets.ca/forum/showthread.php?t=55204
Check out my thread there...
Maybe she is a picky eater and doesn't like what you are giving her? Has she been checked for worms? If she's not eating she could be sick, if she's eating and not getting better she might have worms. My kittens don't have worms or anything wrong with them but they are scrawny too
