Cats fighting in the house

[mved]

I have 7 cats in my house.
* 2 cats of 16 months who have been in my house since their mother brought them at 1-2 months - Cutie(female) and Curious(male)
* 3 cats of 4 months who are kittens of Cutie.
* 1 cat of 3 months - MiuMiu
* 1 cat of 9-10 years - Mummy Returns. She is the mother of Cutie, Curious and MiuMiu.

Last year Mummy Returns brought Cutie and Curious to my house. Mummy Returns left them when they were about 3-4 months old. Ever since then they've been living in my house as pets. But, Mummy Returns returned back last December(thus the name) and stays in our house now.
Mummy Returns often picks up fights with Cutie and Curious, more so with the latter. She just attacks him at sight. Even though Curious is a pretty hefty looking male cat he doesn't seem to be very good at picking fighting. He regularly gets beaten up by Mummy Returns.
Why would mother cat attack her own kid? Does she not recognise them as her kids after 6 months absence? This has been happening even before she gave birth to MiuMiu, so nothing to do with new kitten and MiuMiu gets well along with all the other cats.
Also, should I let them fight and sort it out or intervene which is a better way to handle this situation?

[lilynmitz]

First, please please get all of your cats spayed and neutered, so prevent yet more litters looking for loving homes. Having reduced their hormone levels will also improve their behaviour, as well as countless health benefits such as reducing the risk of cancers. Please take the time to read through and consider this link. http://www.catchat.org/index.php/cat-kitten-neuter-spay

Second, it is common for mothers to drive off their offspring as they get older, and there is no guarantee that mothers/offspring, or siblings, will get on. They don't relate in the same way as we do.

Some cats also find multi-cat households stressful, as they are naturally territorial but being in a close environment can contradict this behaviour. This may be why Mummy Returns left in the past. The fact that she now has come home to find a "hefty" male cat living there, even if he is her son, is probably why she's fighting him off.

To some extent it's best to let them sort this out themselves, but try to find ways that they can get away from each other to some personal space if they want to. But definitely definitely get poor Mummy Returns and Cutie spayed as soon as possible, and any others that aren't yet "done". It's quite possible that the father is Curious, and this interbreeding can result in congenital birth defects. I'm afraid this uncontrolled breeding is asking for trouble, and just adding to the problem of thousands of cats around the country locked up in rescue centres awaiting the chance of a loving caring home.

[Crewella]

I can't add much to the excellent advice above - I absolutely agree that it will help enormously to make sure all the resident cats are neutered pronto!

[mved]

First, please please get all of your cats spayed and neutered, so prevent yet more litters looking for loving homes. Having reduced their hormone levels will also improve their behaviour, as well as countless health benefits such as reducing the risk of cancers. Please take the time to read through and consider this link. http://www.catchat.org/index.php/cat-kitten-neuter-spay

Sorry, I forgot to add that all the older cats have been neutered/spayed already albeit female ones were spayed after their kittens were 2 months old.

Second, it is common for mothers to drive off their offspring as they get older, and there is no guarantee that mothers/offspring, or siblings, will get on. They don't relate in the same way as we do.

So this is likely to become a bigger problem once the cats grow up? Is it a good idea to let them continue living in the same household?

Some cats also find multi-cat households stressful, as they are naturally territorial but being in a close environment can contradict this behaviour. This may be why Mummy Returns left in the past. The fact that she now has come home to find a "hefty" male cat living there, even if he is her son, is probably why she's fighting him off.

None of the cats were previously allowed in the house. I only started taking Cutie and Curious inside after their 3rd sibling died and Mummy Returns left them to themselves.

To some extent it's best to let them sort this out themselves, but try to find ways that they can get away from each other to some personal space if they want to. But definitely definitely get poor Mummy Returns and Cutie spayed as soon as possible, and any others that aren't yet "done". It's quite possible that the father is Curious, and this interbreeding can result in congenital birth defects. I'm afraid this uncontrolled breeding is asking for trouble, and just adding to the problem of thousands of cats around the country locked up in rescue centres awaiting the chance of a loving caring home.

There's no inbreeding thus far as we know which tomcats are father of both sets of kittens but I've already spoken to the vet and we're getting the kittens neutered/spayed in the next 1-2 months before any of them reach 6 months of age.
It's difficult to keep Mummy Returns away from the other cats and quite often she attacks the older cats out of the blue. And even tries to scare off the kittens. Only way for now is to send her out of the house temporarily.

[Crewella]

I don't have a huge amount of experience with kittens growing up in a household, but my experience of introducing various older individuals has tended to show that they go through phases of aggression until everybody knows where they stand and accepts it, and then it all calms down a bit. Even if they still don't like each other, they just learn to keep their distance. I hope that is the case for you.

[mved]

Thank you Crewella and lilynmitz. I am trying to keep them as separate as possible, between 2 of my houses. That does reduce the fights but can't find a way to completely avoid it.