Zelda's former owner suddenly began traveling a great deal. That, combined with the introduction of two other cats into the household, was too much for Zelda; she began to have issues with inappropriate elimination (if you don't know, that means she didn't always use her litter box when she should have). Because this had not been Zelda's habit throughout her life, we think that the negative change in behavior might have been due to circumstances. We'll be monitoring her closely here to see if this behavior continues.