Please Help, 2 Cats New Kitten Aggressiveness.

[Jamesf553]

Hey guys quick question for you. I want to get some advice on this as it is stressing my wife and I out big time. We fostered and adopted two awesome spayed female cats 6 months ago. 1 is 8 months old and the other is about 9-10 months. They grew up together with us and they are the best of friends

We agreed to adopt one last cat and she is a spayed 5 month old cat. Super super sweet. However, boy oh boy do these cats not like each other. I isolated The younger one in a little pen as we don't have a spare room just for her. She is inside a large pen in our family room with a blanket over top.

The 8 month old is fine with her, she growls a little but seems fine. The 10 month old though just will not stop hissing. She goes right up and will look her right in the eyes and for 10 minutes at a time will growl, meow, and hiss.

While I realize this could be normal for a while, what I'm most worried about is the 8 and 10 month old are now hissing at each other. We are wondering if the older one is mad that the 8 month old got the kittens scent? My wife is very upset because she is concerned we ruined their friendship as they are now hissing.

Any advice???

 

[dahli6]

They are working out their pecking order. When it is 2 cats everything is shared half and half. There is no real competition and like you said they grew up together.
The new kitten adds a competitive element that will be worked out in time.
Even the 8 and 10 month old sniping at each other is very normal because they now have to determine who the boss is.
I would schedule some time every day for the three to interact with each other and you and your wife. Floor time, playing and petting. If anyone becomes overly agitated or tries to fight, crate them until they calm down and let the other two socialize with each other.

 

[susanm9006]

Your two older cats are hissing at one another because they are on edge because of the newcomer. It is pretty normal behavior and I wouldn't worry about it. At the age of your three I think they will adjust quickly to one another and be wrestling and chasing one another soon. In the meantime a fair amount of hissing and even slapping are to be expected.