How do I know if shes too skinny?

When I pet Abby I can feel her spine ( on her back)..Is this normal? I feel like shes too skinny?

She stopped eating her old food....so we switched her to Beneful and she loves it , btu she just doest eat all that much? Doesnt seem excited about food , ( well unless its table food).

When I give her wet food to supplment which she LOVES, she gets diarehha( sp?)

Is it normal to feel their spine or am I right shes not getting enough food?

Re: How do I know if shes too skinny?

You should be able to feel and just see their spine and ribs. If you have to press really hard to feel either they are too fat and if the spine or ribs are sticking out noticeably then they are too thin.