If they've been in for more than a few days, they now can't go outside till about April, as it is way too cold.
There are quite old to be entire males together. To be honest, they were probably doing this outside but at night when you weren't around. You know your rabbits best, you need to judge whether it will stay at chasing and jumping or whether it will escalate. If they will be fine, keep them together, but if you think it will escalate I would keep them apart but so they can still see and smell each other, so preferably separated by bars but still next to each other.