Male brother guinea pigs fighting gets increasingly worse...?

I have two male supposedly brother guinea pigs. I'm not sure where they came from or if they really are brothers because I adopted them from a foster child who couldn't keep them... Anyways they have a small cage and are fighting like crazy. They have always fought a little but it keeps getting worse. I tried putting a temporary piece of cardboard down the middle with a little window so they could see the other one but they had a panic attack. Fudge, went running around flipping over his bowls, while Crackerjack, chewed a hold in the window until he could fit through. One has always been dominant but that might be changing. Now it seems like Crackerjack is bulling Fudge. But they will not be separated they cry for each other and simply panic. I live in the laguna Niguel area. I would be able to get them a bigger cage but it would be an outdoor hutch... Would that be better? or to easy to forget