Himalayan kittens & cats in Georgetown, Delaware

Adopted as a kitten, Kiwi is 7.5 now. We have another cat. She is ok with her but will instigate a fight on occasion. We have 2 dogs which she ignores. We had another male cat which she bonded with, however he was old and developed cancer and is now gone. My daughter moved home with us and Kiwi has starting marking my daughter's space. I have tried several behavioral modifications but it has not helped. Prior to this I am not aware of her not using the litter box. This behavior has been going on now for some months. She otherwise acts normal. She really is not a friendly cat except to my husband and myself. She has never done well at the groomers, so I keep her brushed as best I can. Kiwi would do best in a quiet household without other pets. She uses the litter box regularly so I am perplexed as to why she has decided to go elsewhere. I am not physically able to keep up with the extra cleaning. I am sorry to have to rehome her, but I believe in the right home she will be happy.