a lot of things can cause loose stool, but hair balls are probably not one
of them. they tend to cause constipation.
are you sure she has hair balls? cats with ibd (inflammatory bowel disease),
which my Lucy has, can vomit in a way that looks like they are hacking up
hair balls, and can also have loose stool on and off. The best thing for that
seems to be home-made diets, and most of all to be consistent and stick to
one food. the most digestible of the store-bought foods for ibd seems to be
Innova EVO, which has no grains, as grains seem to irritate ibd in cats. you
might want to try that, and not change or add any foods for a while--
switching
back and forth is the worst.
michelle