I'm sure this has been covered a thousand times before but can't find anything that's exactly like my situation.
We have a three year old cat who has always been great, goes in and out independently via catflap, generally stays close-ish to home and indoors at some point every day. Eats well, good behaviour etc.
We got a second cat three weeks ago who was 20 weeks when we got her from the rescue centre. We did everything we were told; kept her in a room on her own for a week, introduced them slowly and didn't force any interaction. Our first cat has reacted by barely being in the house. She's nearby but hardly comes in to eat and wants to go out immediately afterwards.
It's been quite upsetting and we're not sure what to do. We got Feliway Friends on the advice of the rescue, but since our first cat is hardly home, she's not benefitting from it. I know they can react quite strongly to the arrival of a new cat, I just don't know what to do for the best. Wait it out and hope???