I took in an 8-month-old female stray about four months ago. The vet checked her out and she's fine, but I cannot get her to poop in the litterbox. She'll pee in it no problem, but she poops in the bathroom sink!
I started covering the sink with a board, and now she's pooping in the floor in random areas.
I have three other cats, all male. I have seven litter boxes in three locations. I've tried different brands of cat litter, shredded newspaper, and old towels (per the vet's recommendation) but nothing seems to work.
Today I left the sink uncovered and she'd pooped in it. Any ideas?