Is there a reason she is only eating wet food? Many times wet food is what give kittens and cats runny poops. Is there a dry food that you can try, that will enable the poops to firm up. Or boiled chicken and rice? Rice would help too. I'd definitely not feed wet food to an animal with chronic runny stool issues. I know we didn't give wet food to any of the kittens at the shelter if they had runny stools.