I have a 2-year-old lionhead/dwarf rabbit who is very timid and shy and on rare occasion a bit naughty. She lives in a bunny cage we bought for her from Fleet Farm that has a slide-out tray on the bottom so we can clean it. Cleaning it THAT way isn't...well...you know, a PREFERRED way to keep her cage clean, so we're considering litter box training. Is it too late to litter box train her? If not could I get some methods? Much appreciated!