We've been having all-around poop problems with our six-year-old cat for about a year and a half now. She started out by pooping outside of the litterbox. We took her to the vet for a thorough checkup and they could find nothing physically wrong with her. We were told to quarantine her to a room by herself for two weeks, with her food, water and litter box in the room. We've done that several times, and each time it works for a few days and then she's right back to pooping on the floor. This last time, though, she hasn't pooped on the floor, and it's been about a month. In the last few days, though, she's started taking a small ball of poop out of the litterbox and batting it around like a toy, going all through the house and down the stairs with it. It seems she goes from one odd thing to another! Help! Is she already getting senile?