Get a Booda Dome kitty litter box. Ashley pointed it out to me some time ago,for a kitty we had. Wonderful box..and they can't get to the litter. Amazon has great prices on them! I got the noe with the steps,can't be without this litter box with these dogs...they like kitty crunchies to
Corbinam posted a funny story about a Booda Dome experience..."We bought one of those Booda litterboxes and came home and Bentley had gotten the lid stuck on his head and dragged it around, and then ate the poop."
I guess it depends on how determined of a brown noser you have

The top-entry type is really the only dog proof box I've found so far (and you can make them yourself for way cheap). For your pup's funky stool in the meantime-pick up some Fortiflora, feed her carrots, celery, or pumpkin and that should help settle her tummy. (I'm sure you know the drill by now
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(there's that emoticon again....) We're going to try the 'top loader' and see if our three kitties will accept that. Meanwhile, I have a baby gate propped in front of the cat box, and braced by a door. When Olive gets desperate (like she was today because of her fast following the diarrhea), she will figure out a way to pull that over to get to her 'snacks'. Sometimes I wish she weren't so smart...