Introducing kittens to cats

[Rosella moggy]

I have moved the two duplicates to avoid confusion 

  to Purrs.  Very much hope you enjoy it here and hang around 

Sounds like you are doing very well.  Have to expect a bit of hissing to start with.  Hopefully just a question of time and things will become easier when the babies are allowed outdoor access ....... after they've been neutered of course.   I think vets are happy to neuter earlier nowadays.

It would be lovely to have names and pics too 

[pussinbooties]

Sorry for the duplicates. I didn't think it had worked

[pussinbooties]

Hello there.
I got two 9 week old sister kittens four weeks ago replacing two older cats who died. I also have two two year old siblings ( brother and sister).

I kept newbies in a room for at least a week. Other cats were aware of them as they could see them from the stairs ( door with glass upper) and hear them jump at the door.
Female oldie's behaviour changed... Grumpy towards brother and staying out most of the time. I guessed that was redirected aggression so decided to keep kittens apart from others for longer. Also purchased feliway diffusers for rooms and tried scent swapping by allowing both parties access to different parts of the house.

Boy cat got access to kittens sooner as he was about more. He'd watch the kittens play and just hiss if the got too near or gently tap them as they went past. He's still at this stage.

I am forcing the issue with his sister and trying to keep them indoors at night ( kittens in different part of house overnight). On the whole the relationship between them is ok. I will use interactive toys with them and they'll play. Will walk past each other most of the time without issue and I think great they're back to normal and then sis will give bro a warning hiss out of the blue. He doesn't seem too bothered by her moods.

Now the kittens.... over the last couple of days I've made the comparative oldies stay indoors  with 'a day off to do as you please' in between. Today is wet so an  'indoors training day'. I don't know what is acceptable at this stage. Oldies watch kittens antics and just give a hiss when they get near. I had older female on bed with me and the two kittens and she stayed there giving a low grumbling growl as if to tell them not to get close to her.

Is this acceptable? What I should expect at this early introduction phase? Oldies not best pleased. Noses put out of joint and not being best pleased at cat flap being locked...... but I am trying to get them to stay in at night anyway as there is FIV and stray cats around. Should I be grateful that there is no fur flying? or should they not be hissing now?