How much is normal? Siblings being horrible to each other.

[Itsfab]

DD is 11. Her brothers are 9 and 13. She is mostly horrible to the youngest and that is because the oldest stays out of the way but meal times are hell as they are sat together.

Tonight she has gone mad over DS2 looking at her for a millisecond.

All lie to get the others into trouble. Hard to deal with if I haven't seen what happened, or that nothing did.

It just makes me so sad. We aren't a family .

She actually wouldn't care if the boys weren't here.

Most of it is normal and some of it is ( very Sorry) something to do with you and your DPs Parenting. You don't mention their DF
All children fight, but if it is really getting you down this much then I think you need to look at how you Parent and how you deal with the issue of them fighting.

My DF was toxic, without the slightest respect for us. When he was older he complained that we had no respect for him! Duh!

Are you quiet and reasonable and always respectful towards them ?
If you are ( please accept my apologies for seeming to flame you) then I would be looking to read some books on teenagers as your Dd is coming up to Puberty.
The important thing is that you remain calm. You are the adult and you should set the boundaries. They can control them selves ( I bet they are well behaved in school)
Put into place sanctions and follow through. Don't weaken and feel guilty. Don't shout ( otherwise they will shout at you) and be consistent even if they moan and plead and try to blame each other.
Best of luck

It is 100% my fault she is like this.

DH is here. At a loss too.

Why is it your fault?

No it is not 100% you. It can only be 50% because your DH is half of the Parent.
Sit down together and devise some rules.
Ie. what you will and will not tolerate.
Withdraw as sanctions, phones, iPads, money etc if they don't moderate their behaviour. Make them! you should be the boss in your own home as you are the adult. Stand firm against all entreaties to get their phones back. Children can survive without phones.

All sit down for an evening meal, all phones collected up, TV off and talk. If they kick off, then the phone stays confiscated. They may run off to their rooms and slam doors, just carry on eating. Clear the food up and don't respond to any sulking. They know how to manipulate you.

The firmer you are In the beginning of this new regime the less time it will take to have an effect.
Do an outdoor fun thing together as a family, or an indoor game . Play cards all together. Such as trumps. Whoever wins a trick gets a jelly baby. Do A large jigsaw together. Something to do where they are cooperating, not fighting.

You say you are not a family. How much do you do together ?
Have you never seen Super Nanny ? She deals with fighting children in families all the time and makes the home a happier place.
These are her suggestions.
Some of it was because the Parents did not set strong enough boundaries. Some of it was because the parents screamed and shouted and pulled the children about because they lost their rag. So the kids thought it was Ok to do the same.
Some of it was because they did nothing together as a family and the Parents were not strict enough. The children were bored and fighting was a way of getting attention. Yours are all still young enough for you to make them do things.

Mealtimes are now anxious times in your family. You are anxious and anticipating trouble and it is self fulfilling.
Get some books and read them about parenting and teenagers. Be very firm and don't give way.
They have a right to behave like teenagers and you have a right to behave like a Parent.
Make sure that you are not depressed. Get treatment if you are as everything gets out of perspective when you are depressed.

When my son helped himself to a bottle of my expensive Whiskey and took it with him to a party, I stopped his pocket money until it had paid the equivalent of the price of the Whiskey.

Best of luck.l