I foster cats and recently got a real sweetie in. I told my mum and sister about her and they thought she sounded like the perfect companion for their current cat. They applied to adopt her and were approved, and I delivered her to them last weekend.
We let the newbie settle in for a few days and swapped scents as we read we should. Initially they were quite calm with each other - existing cat was interested and wanted to play. New cat has become progressively meaner towards her and given the opportunity will stalk and try to chase her. The reports I'm getting are that existing cat is getting progressively unnerved by the new cat's presence and they regularly have spats that upset my mum and sister. They are having regular alone time to decompress after each introduction.
Existing cat does nothing aggressive to provoke these "attacks". It's been less than a week but they are seeing things go backwards, and their beloved resident cat being "bullied" by the newbie.
Anything you can suggest to ease the transition?