Having trouble introducing cats

[SeismicNick]

Hello, hoping someone can give some advice on this. We had two resident cats, Smokey and Bebe, almost 2 years old and brother and sister from the same litter. Recently, we decided to adopt a more elderly cat, 13 years old, that was in the shelter. She is very sweet and loving. Her name is Petal. Up to now, we have done everything we have read about introducing cats. Giving the new cat it's own secluded area from the resident cats, feed them together on opposite sides of the door, and we have just started switching their places so they can learn each others scent. However, when Smokey and Bebe end up together in Petal's area, there is a lot of snarling and hissing and fighting between them. It seems to get worse when one of us enters the room. Petal however, is very calm and just curls up wherever she pleases in Smokey and Bebe's area. I can't really think of any reason why Smokey and Bebe would be fighting each other as opposed to maybe hissing at the door where they know an outsider is in their territory. Other odd things to note. On the whole, Smokey didn't much seem to care about Petal's presence up until Bebe started hissing and throwing a fit. Now they both hiss and growl at Petal on sight. Petal, however, barely pays them any mind unless they get too close to her (about 6 inches away). Overall, not really sure what else I can do as of right now. I'm really hoping someone has some ideas. I'd really appreciate it.

[booktigger]

First question is what do you mean by recently?

[Crewella]

Hi, it would probably help to know the timescales involved here - how long have you had Petal? It sounds as though the other two are feeling insecure and taking it out on each other a bit, but some of the snarling and hissing is to be expected in the early days. A Feliway plug-in might help, and I've linked to the Cat Chat advice pages on cat hierarchies and also agression, which might give you a bit more understanding of what might going on here.

http://www.catchat.org/hierarchies.html

http://www.catchat.org/cat_aggression.html

[SeismicNick]

A little under a week at this point. I fully expected all the hissing and whatnot towards Petal. All the aggression between Smokey and Bebe really threw me off though, considering they are litter mates and know exactly who each other are.

[booktigger]

I wouldn't even be feeding them the other side of the door that soon, never mind swapping scents. You need to slow things down with your cats reaction

[SeismicNick]

Fair. Can you give me some sort of timeline or a link to one to follow, perhaps? That would be extraordinarily helpful.

[OHWS]

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[Crewella]

I agree with OHWS. I once introduced a cat to the household after a couple of days because she and my big boy, Daz, were calling to each other through the door and he basically camped outside her room until I let him in (they became real partners in crime). She was hugely sociable and just slotted straight in to the group, no fuss. On the other hand, It took months to settle others in. Just play it by ear and let the cats themselves dictate the timescale - no point in moving on to the next stage if everybody is still struggling to cope with the last one, no matter when it is.