New owner- Guinea pig chasing other

[J2983]

Hi. I'm a new Guinea pig owner - my partner surprised me and our 5 year old after we have been speaking about Guinea Pig's for a while. We have had the for 5days.
We have 2 - both male. He was told they were brothers of the same age altho one is smaller than the other.
The smaller of the two Stanley keeps chasing and we think nipping the bigger of the two Jimmy. 80% of the time they will happily Co exist in the cage or run together.
I've read it's to establish dominance. Jimmy never fights back or shows any dominant traits so is obviously happy to be the lower ranked Guinea pig but Stanley still chases him.
Funnily enough Stanley is a lot less confident than Jimmy in every other aspect- best way I can describe it is its as if Stanley has small man syndrome. He is smaller and still a bit jumpy and not as comfortable with us yet as Jimmy is but will bully Jimmy like he is trying to prove himself. He will happily snuggle up with Jimmy and share food with him chat to him etc then all of a sudden he is chasing him around again.
They are in a fairly big cage and we have a big run which they go in a couple of times a day.
I've read so many different things online from this is perfectly normal behaviour and once they settle in more it will stop to that we need to separate them immediately / permanently. But again everything I read seems to be based on two Guinea Pig's fighting for dominance but Jimmy is showing no sign of having issue with Stanley taking the dominant role. Any advice would be much appreciated

 

[Dollyx]

I've had this same thing with my two girls and it is normal! When guinea pigs are put in a new cage, the dominant one will always re-establish that dominance, even if the pigs have been together before you got them. My girl Pigeon does not fight the other girl, Dolly's, dominance, even so Dolly still establishes that dominance despite Pigeon not fighting for it. I'd say to just keep an eye on them and make sure nothing gets violent

 

[Piggies&buns]

It is very normal behaviour for two young boars (I have two boar pairs myself - a 4 year old pair and a 4 month old pair).
The dominance won’t completely stop though but it does settle , it’s something they will do throughout life as they maintain their relationship. It’s good that he is accepting his role as lower ranking but it does not mean the other will stop.

Any new environment will cause them to go through increased dominance and reestablish their relationship. This takes around 2 weeks so if you’ve had them for 5 days then they are only just starting their process.
I would leave them in their cage and don’t put them in the run for a while yet. Let them settle to their new cage (and with each other) before removing them from it. We recommend that they are left to settle in for the first week without being handled, only fed and watered. In the second week you can sit by their cage and talk to them, start to offer hand feeding etc to get them used to you while they are settling in.

You’ve used the word bullying. Bullying is a set is sustained behaviours which will see the submissive piggy become depressed and withdrawn. The bullied piggy may constantly be chased away from food and consequently you may noticed weight loss at each weekly weight check. They may refuse to leave their hides.
This kind of behaviour is grounds for a trial potentially leading to permanent separation. A full on fur ball fight is also grounds for separation. Dominance is not grounds for it.

Piggies are teenagers between 4 and 14 months of age and it is during this time with hormones raging that you will see a lot of this kind of behaviour.

With boars, a lot of space in their cage is essential - a 180x60cm cage or a 5x2 c&c. Anything less can cause issues with lack of space.
All hides need to have two exits and there needs to be multiple resources in the cage (two hay piles, two water bottles, at least two hides).
Also ensure you handle the dominant piggy first. It is his right to have the pick of everything and if you do something for the submissive piggy first then it can cause the dominant to feel the need to enforce their position more.

The guides below will help with further information in keeping boars

A Comprehensive Guide to Guinea Pig Boars
Boars: Teenage, Bullying, Fighting, Fall-outs And What Next?
Dominance Behaviours In Guinea Pigs

 

[Cheekypigs]

My experience is that chasing never really stops, even with a pair who get on great! It's just what piggies do, especially boys. The post above gives great info. The rule of thumb is that if they're not drawing blood, and the chased piggy still seems happy overall, let them be.