Originally Posted by Jen
You should have at least 5 litterboxes for one, but I don't know how much that would effect spraying, but they might be unhappy all having to go in just a few boxes. If you have 5 or more then great, another thing you can try is a Feliway Plug ins. Perhaps multiple plug ins, they are rather expensive but they are for this kind of problem and I have heard they work miracles sometimes.
I, personally, think 5 litterboxes is a little excessive. I would say to have two. I have two cats, and one litterbox is just fine. I would say the ratio of cat to litterbox should be two cats for every one litterbox. It sounds like you keep them VERY clean, so I wouldn't worry about two cats in one box.
Some things that should help...
Sometimes kitties get very finicky about exactly how their litterbox is set up, and where. Sounds like that's the problem here.
Our boy, Hobbes, did the same thing, and it turned out he wanted one litterbox to poop in and one to pee in, he didn't like hooded litterboxes, and he liked it pristinely clean. I found a couple websites that helped me understand exactly what it was that I could try that would help, and it really did. One good thing is the fact that he's now outgrown his pickiness about wanting two and wanting them in such perfect condition, now that he's about a year old! Hopefully yours will do the same!
Here are a couple websites that should help:http://www.larimerhumane.org/services/litterboxinfo.cfmhttp://www.thepetprofessor.com/secA...es_and_cats.asphttp://www.heartlandhumane.org/pub/petcare_litterbox
A couple tips:
Cats don't usually like the plastic liners some people use in litterboxes.
Some cats don't like the hooded boxes.
Cats at times don't like the box to be anywhere that they also have to eat and drink.
Sometimes the problem is just that the box isn't somewhere private enough. They only like to "go" somewhere that is low-traffic, quiet, and very private.
If you try these things, as well as the Feliway spray, and you find that they're still going elsewhere other than the litterbox, I would consider getting them checked out by the vet. I would also say to clean the spots with an enzyme-based cleaner (kinds you find in a pet store, so you know it's ok for cats), so you rid each place of bacterial trace...this should help prevent them from continuing to go there.
Hope all that helps!
Let us know how it goes!