My Cat Is Pooping Outside The Litter Box What Do I Do?

[jraybu84]

My cat recently started pooping outside the litter box. I took him in for a medical check and they did the full work up and found nothing wrong with him to include pain. I have changed the litter in the boxes and that did not help, I have moved the litter boxes to different locations and that has not helped, I have tried encouraging litter box use by putting him in the litter box and that has not helped. He has been using the same litter boxes as my other 2 cats for the past 6 years and this started happening out of the blue. When I seperated him in another room for a week, he started pooping in the litter box again, but as soon as I let him back in the rest of the house with the other 2 cats, he started pooping outside. We have 3 cats total and 4 litter boxes. He pees inside the litter box but poops outside. He is an older cat (around 13) and he has been overweight since we got him. He does not have UTI before anyone suggests that. He has been tested multiple times. It must be some sort of behavioral thing with the other cats right? I can't just keep him isolated in a room for the rest of his life. How do you solve this problem?

[lankeela]

Put him outside like a normal cat to go and poop in a neighbours flower beds.

[pastafreak]

Have you changed the brand of litter? If not, and he's not reacting to a new one....then try a different brand. Some litters bother cats paws. Does he have difficulty entering/exiting the litter tray?
Has his behaviour with the other cats changed?

[Old_Geezer]

Perhaps he's gone all shy in his old age. Get him a box with a curtain.

[douglas9401]

It may just be thinking "Outside the box".