Male bp's can breed starting at around 350g, which still a small snake. It depends on the male though, not all would breed at that size. I personally house them all separately, and that's just my choice. No need to have scientific backup for me, it just makes sense. It's up to each individual keeper to make that housing decision. You WILL end up with babies at some point in the near future. That may sound like fun until you try to find homes for normal males and such. I don't know your situation, so that may work for you.
On a side note, that little reduced guy on the top left in that pic is a smoker!
Good luck!