Male rabbits are fighting!!

Hi
Yesterday I got 2 male rabbits. I was told they are half brothers. One brother, George, was the runt of the litter.

His mother died directly after giving birth and so he was hand raised. The other brother, Lucas, has a different mom but same dad, a flemish giant.

They were kept in a large horse stall with about 15 other bunnies. Most of them were young males, some were older females. When I brought them home yesterday, they cuddled and slept together in their cage and ate together. Today, when I let them out to free roam, Lucas started chasing George and it ended up in a big fight. George then stayed in the corner of the room while Lucas explored.

Back in their cage, they are completely fine with each other and are back to cuddling. Is this normal? Should I keep them in their cage for a few days until they get used to being here?

Should I free roam separately?

Thanks for any help