My Daisy is kind of half and half. She will use the litter tray and knows what it is for, but does quite often pee next to it instead. :evil:
I am really hoping she will stop doing that once she is speyed.
What kind of litter trays have you got? Also, have you tried putting in something they have peed on so it smells like them? I'm sure you've already tried it, just trying to think of ideas!
Also what do you put in the litter trays? If they have similar things to their surroundings, like hay in the litter tray and hay everywhere else, it could confuse them. I keep mine on carpet and keep straw and newspaper in the litter tray, and hay for eating. My rabbits all immediately associated newspaper with a toilet, I don't know why.