Getting a kitten with a bad tempered adult cat

[MagdalenLaundry]

I have a rescue cat. He is very grumpy
I have started keeping him in at night as he was fighting
I love him but he is not really a family cat. Only likes one person and one stroke a day
There are kittens needing homes and I'd love to get one
How do you cope with keeping one in and 1 out?
He uses a window, won't wear a collar
And will he accept a new one. He was in a home with other cats so he must have found some tolerance

Hopeful bump

What do you mean by keeping one in and one out - do you mean when you first get a new kitten?

Have you a cat door?
Where does cat spend most of the time, and will this change as the weather gets colder?

The cat is in and out throughout the day using a window
I meant for the time the kitten had to stay indoors. I guess older cat would have to be in the one room

It sound s as if it would be very stressful for your existing cat

Get a microchip cat flap so only the old boy can get in/out

Old boy won't wear a collar
I'm calling him old but vet thinks he is 3 so not old really
He was in a cats home that was a house so never confined to a cage and he had to live with other cats there

Microchip catflaps work on the chip though, no collar needed. Would be an ideal solution, surely?

You could be describing our cat - rescue cat, grumpy, won't wear a collar, refuses to use cat flap. It was our vet who actually suggested we get a kitten for company, but to make sure it was female as two toms would've fought like cat and, um, cat. Fast forward 18 months and grumpy cat has been transformed by kitten's presence. He's affectionate, plays and hasn't taken a swipe at/bitten any of us since she arrived. But he is really old - nearly 12 - so don't know if a three-year-old would be as happy.

Oh and she happily uses the cat flap - we showed her how to use it - while Lord Muck still likes the door open and closed for him!

Sorry didn't read properly
He is microchipped so it would work if he could be persuaded to use a cat flap
I would only consider female kitten so he can keep his top Tom spot

He was in a cats home that was a house so never confined to a cage and he had to live with other cats there

I think the key phrase here is 'had to'

Cats are selectively social and those raised together as kittens are generally more likely to get on. What are the benefits to your existing cat? It will potentially be hugely stressful for him. Many people fail to recognise signs of stress in multicat households. This video is really useful
m.youtube.com/watch?v=bPqreEUV5vM