Help, is this normal behaviour....

[Fightclub19]

My SS are 12 and 14, so youngest started high school last September, since then I have noticed that their behaviour has deteriorated dramatically and as my children are primary age I just wondered if this is a phase they are going through.
They argue All. The. Time. The slightest things erupts into a massive kick off. They can't kick a ball about in the garden without it ending in a fall out.
They name call with each other, and wind each other up to the point of it being ridiculous and they sound like 5 year olds. We tell them to stop, they just carry on.
They physically fight each other, to the point, punches are thrown, the other day one had a bust lip. Sometimes this starts off as a play fight but as usual it ends up with one of them in tears.
This is just a few examples and it isn't one or twice a month, its every single week, for practically the whole time they are here.
We are at a loss as how to deal with this. We separate them, it works for about an hour. We ask why they do it, because we're kids is the reply, they don't see any wrong in this behaviour. We've spoken to them and said, it's not acceptable behaviour in our house it falls on deaf ears.
First and foremost I want this behaviour to stop, but I have noticed our younger children saying let's play fighting and they're starting to hit each other. I don't want this cycle repeating again.
I know kids, brothers, fall out, but is it normal to be all the time. I had a DS and DB, so no real experience of this and DH, was the youngest with 2 older DS so again not much experience. Any thoughts appreciated and any advice on how to cope / deal with it I'd be very grateful for. Thanks.

My middle too are 12 and 15 and they can bicker, fight, name call and be best mates throughout the course of the day. The 15 yr old really enjoys winding up the 12 yr old so he flips...we intervene when it gets out of hand and they are separated. What your describing does sound worse and I wonder if they are acting out as they are at their dads. I don’t know the back story or whether your DC are there half siblings but sounds like something is driving there behaviour. Be interested to know if there the same when at there mums

Sounds pretty normal to me, I grew up with brothers and lots of male cousins.
Although I would be trying to separate them before punches or physical injuries are caused.

Maybe separate them early on during their visits, so SS1 will go to the shop with dad and SS2 can stay and help make dinner with the younger siblings for example. Keep them busy or they’ll be bored.
From my experience 14yos on bored easily and not really into “family time”. Does he have a bike / friends or activities he can do whilst as your house? I think often NRPs (if they have the kids less than they’d like) expect the kids to just be excited to be with them as and hang out as a family. The reality is they get bored easily and then try to make their own entertainment... in your case by play fighting or annoying each other.
I remember the joy I’d take in annoying my brother at that age to them it’s funny

Also try not to be too precious about your own kids, I guarantee you no matter whether they’ve seen it modelled by their older siblings, they will fight / annoy each other/ argue at some point anyway.
It’s very easy to think “My kids are angels and they’re copying them!”
It sounds like your kids are a lot younger, you’ll see when they’re older that sibling rivalry annoying each other is par for the course with teenagers.
It’s like when you have a newborn and see a toddler tantrum and naively think “that’ll never be my child” 😂😂😂
Trust me, they will do it anyway.

I think its normal for them to argue but the physical fighting where someone is hurt sounds like its gone too far.

@aweedropofsancerre yes they're all half siblings, and do wind each other up until one of them flips. Their mum says they are the same with her, they say they are allowed to do what they want, although mum does not agree with this!!.
@TheChain - they do have bikes, computer here etc, but the 14yro doesn't have any school friends local but the 12yro has a couple who live near. He does sometimes go to his house. We also have a field near us where they are allowed to go for a kick about, but they always come back after falling out!! I honestly don't think our younger 2 are angels, definitely definitely not, I just don't want them getting older and thinking what they currently see is the norm, to the point they are causing injuries to each other. Its tiring for us to keep referring fighting and separating them, but we will be persevering !!.
@PinkCrayon - I agree that causing physical injuries imo it's gone way too far. But we can be physically telling them to stop and they just carry on until DH is actually pulling them apart- even then someone has to have the last dig.
I know this type of behaviour, name calling and winding up is probably very normal between siblings, it was the extent (physical injuries) that concern me and the fact it is all the time. It is probably a mixture of age, going from primary to high school etc. Hopefully it is a phase that will pass soon - fingers crossed.

Do they behave like that at school?

My teens may bicker and name call but they've never caused physical injuries to each other.

My 12 year old and his friends enjoy play fighting but his older siblings wouldn't fight him because of the size/strength disparity. (Oldest child is over a foot taller)

@pikapikachu - as a general rule no they aren't like this at school, as far as I know there has been a couple of separet incidents involving both SC separately, if that makes sense !!. And to be honest I don't know why the younger one even entertains fighting with his older brother, yes being older he is generally going to be bigger and taller , but he is also a little overweight, just 'the puppy fat stage' I would imagine. Once he has a growth spurt he will probably even out.