if she was sick, dont you think she would do it all over? she uses the same room, and same well, along the wall.. she sniffs first before she does it, thats how i know shes getting ready to..i see her walk right past the box... i tone my voice and tell her no, go to box, and she slowly goes to the box, like shes in trouble or something. i dunno . she dont act in pain or if anything is wrong.. she has been to the vet after she started doin it, everything was fine. she has no problems with my bunnies.. the previous owner of this house did have cats.. maybe the smell isnt totally out.. what brands of cleaner do you recommend