Is my guinea pig happy or missing his brother?

[aspiring_dino]

For some background context, I have 2 young male guinea pigs. The girl we got them from said they were bonded, we quickly realized we really don't think they are. They've had some behavioral issues lately, lots of little fights but it got to a place that we were uncomfortable with, lots of mutual teeth chattering, some lunging, chasing out of areas so we upgraded them to an even bigger cage, added two lofts, and set it up so we could completely separate if needed short term or long term.

There was one day a couple weeks ago we had to completely separate and it was really good after we separated them for 2 days then reintroduced them, they were playing with toys, loving their lofts, no fighting, occasionally even snuggling up in the same spots which is something they had never done before! They became a lot more vocal for the first time, one would be sleeping and the other would be running around, wheeking, popcorning, playing in the lofts.

These last 2 days there was some more behavior we were uncomfortable with, a lot of chattering, chasing, and now the older one sitting at the bottom of the loft ramps (even though we have 2 ramps for each loft its taken the little one a little longer to get the hang of it/confidence on the ramps) so the little one won't come down. We separated them for a couple hours just because they started fighting in the loft which caused one of the supporting pieces to come loose so we separated them while we fixed it. However, while they were separated they kept putting their noses to the grids that separate them, eating next to each other at the grids, and the little one was digging at the grids. The weirdest thing we noticed though was that when the older one is sleeping on his side or in his own loft doing whatever, the little one will kinda wander around his half of the cage squeaking & talking like crazy. We can't tell if the little one is so vocal now because he can't get to his brother (not actually brother, uncle if we're being technical) or if he's so vocal because he is happy that his brother can't get to him? Sometimes the younger one will go into the ramp and make the same vocal noises/squeaking which we were worried it was because he was afraid to come down at first but then he would do it in the loft while popcorning so we assume it's because he likes it. When we separated though, he wasn't popcorning he was almost wandering.
Additionally, is it bad if when they start to get too nudgey with each other if we separate for a couple hours until they settle down a little?

 

[Piggies&buns]

You say young - what are their ages? If they are between 4 and 14 months of age, then that means they are hormonal teenagers and seeing dominance is perfectly normal. It doesn’t mean they are not bonded.

Were they actually full on, blood drawing fights or just dominance (chasing, mounting, rumbling is just dominance)?
You must permanently separate for a full on fight - that means the bond is broken and separation must be done permanently.

You don’t separate for dominance, but if hormones get too much and things get tense you can give a couple of days separation to let things settle (a few hours isn’t likely to be long enough). Then try a neutral territory reintroduction and let them make their decision about the relationship. If they like each other And want to be together, then they will go back together. What you can’t do is separate frequently as that can cause further problems - they need to be able to sort things out between them and separating each time will cause them to need to reestablish every time you reintroduce thus causing further dominance.

If there is a problem going on, during the temporary separation it’s the underpig’s reaction you go by. If the underpig perks up and seems happier to be away from the dominant piggy, then that can often mean the bond is a problematic one and the separation might need to be a permanent one (the neutral territory reintroduction will give the answer)

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

 

[aspiring_dino]

You say young - what are their ages? If they are between 4 and 14 months of age, then that means they are hormonal teenagers and seeing dominance is perfectly normal. It doesn’t mean they are not bonded.

Were they actually full on, blood drawing fights or just dominance (chasing, mounting, rumbling is just dominance)? You must permanently separate for a full on fight - that means the bond is broken and separation must be done permanently.
You don’t separate for dominance, but if hormones get too much you can give a couple of days separation (a few hours won’t be enough to let hormones settle) to let things settle. Then try a neutral territory reintroduction and let them make their decision about the relationship. If they like each other And want to be together, then they will go back together. What you can’t do is separate frequently as that can cause further problems.

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

The older one we were told is about a year and a half which we think checks out. The younger one we were told was 6 months when we got him but we really think he was closer to 3 or 4 just based off his physical development, though he was in a very small cage (about the size of a midwest one) with 4 males so we recognize he could be smaller because he was being bullied and not receiving enough nutrient.

In the beginning it was just un-relentless chattering, mounting, and chasing but then when we separated them for two days it was because they were fulling lunging and I think trying to nip at each other- I say I think because my roommate and I jumped up off the couch when we looked into their cage and saw them fighting since it had never been as physically intense before and they were lunging and jumping and us jumping to our feet scared them enough for them to scatter into separate areas. Though, for a good month to two months before this bad fight, the mounting and chattering had gotten a lot better than it had been in the begging. We think this fight was hormones because it had been so good for a while then seemingly out of no where got really bad all of a sudden for a week then was better after a break from each other.
The only time we've ever found any kind of scratch or anything on them was a while ago on the older one's nose. I think part of the issue is that the younger one is very fiesty and has a very big personality, when the older one is eating he will be all up in his rump with his nose we thinking trying to eat his poop. The older one tries to ignore it but gets annoyed and will chatter and chase him away until his stops. Other times the older one will go up to the little one whether he's sleeping or eating or whatever and will just push his nose into the little ones side or hip or belly, not biting or anything just kinda poking him, but the little one gets annoyed and he will try to turn around and nip at the older one. The little one actually got him on the nose one day when this happened and thats the only blood/nip/scratch we've ever found on either of them.

To what extent do we let them work out their dominance? And when do we assume it's hormones and need a break? or even that they can't be together anymore? I know its a lot harder when they're closer in age but its just so hard to know when the little one is truly being bullied and we need to step in or we need to let them figure it out...