One cat has suddenly turned spiteful & is hitting, chasing & generally terrorising other 2

[TheOneWiththeNicestSmile]

Two are 2-year-old sisters, the other is a 10-month-old kitten.

It's one of the sisters who is being a bitch

I can't think of anything that's changed recently, apart from the fact that we now have a cat flap. One of the bossy behaviours is insisting on being first through if there's a race, & also crouching on the doormat to intimidate the others when they want to come in from outside.

She is hissing, spitting & bashing the others any time they're in range. I have intervened a few times - I don't know if that's wrong?

Help, please!

Have they always been used to going outside? And are there any new cats on the block who are coming round to visit?

Thanks, cozie

Until we got the cat flap I kept the door open for them. The flap is quite small though & the grumpy one is the least keen on using it - maybe that's why she's cross (it's the Sureflap microchip one but I haven't registered their chips yet so it's not clicking). They're all small cats so it's not too small, just snug

No other cats causing trouble afaik. We have a small back yard with tall walls all round so it doesn't invite entry but the grumpy one has been going further afield than the other 2.

This morning when I came down the kitten was hiding in a cupboard & seemed petrified so goodness knows what happened last night.

I read an online article suggesting 'scruffing' the aggressor during an incident - pressing her down by the scruff, as a mother cat would (possibly with added hissing ) until she relaxes. Any ideas on that?

All calm atm anyway - kitten ok now & grumpy cat sharing space. Grumpy getting lots of strokes when being calm & relaxed!

I wouldn't scruff a cat. She'll just think your being mean to her.

Oh it said only do it gently!

It's just holding her in place & a) stopping her doing what she's doing & b) reinforcing mother's behaviour training

Touch wood she's calmer today anyway so I'll monitor the situation

I thinks it's bad behaviour sparked by a "new thing". They don't like change.

Well I'm guessing it's that too, but it's not new new - it's been in about 4 weeks

Maybe some feliway might help? I've got 2, mother and son and the mum goes through phases if being quite aggressive and bullying with the younger one. Feliway plug ins really help break the cycle for us but I'm aware some cats don't respond to it.

I wondered about Feliway, Umblub...

If things stay the same (or get worse ) then I'll give it a go - glad to hear it works for you