|Originally posted by valanhb
Perhaps it could be as simple as she's telling you where she would prefer to have a litterbox (just around the corner from the current one). The current one may not be as private as she would like.
Try putting a box where she is defecating, and if she starts using it regularly then you can work on moving it to your desired location. Move it tiny bits at a time, like 1-2 inches per day, so she doesn't really notice that it's moving. Little by little you'll get it to the place you like.
I think Heidi has a great idea! I know that having a litter box in the hall will be a big pain in the rear...but it will be temporary. Just remember to move the box only a little at a time so the cat doesn't realize that it is slowly making its way down the hall to the place where you want the box to be.
Also...she may be telling you that she just isn't comfortable with where you have the boxes right now. It is possible that if you put a second box in a completely different room, she may start using it instead of the hallway. If the boxes are in a place where she feels vulnerable while she is having to sit and concentrate she won't use the box there. A quick pee in a scary spot isn't as uncomfortable as taking a poop, which takes longer and makes the cat feel more vulnerable. For some cats, they prefer their boxes to be out in the open so they can see the comings and goings of others...this way they can easily escape if they feel it is necessary. Other cats prefer hidden boxes where no one can see them while they are doing their thing. If the litter boxes are in a closet...this may be her way of telling you that at least one of them needs to be in a more open place. If this is the case, you can put it in a corner of a room and then surround the box with pretty house plants so that it isn't noticeable.
Also...the only time any of my cats have pooped outside the box was when they were sick. So, perhaps a vet visit will be a good idea.