The recommended way to introduce sheep (especially males) to each other is to put them in a very small enclosure, like a stall, and let them jockey for pecking order position. This way none of them can get up a head of steam and do damage to any others.
So when I looked in the pasture and noticed that our new boys had gotten into the side with all the old-timers, I realized my plans had been foiled. Somehow, they managed to get through the stall divider into the other realm. (I wish I had video of THAT maneuver!)
Here is a little footage of the "Plan B" way to introduce sheep to their new pasture mates.
I did end up putting everyone back where they started, and I may try them together again tomorrow. That is, if they don't sneak over there by themselves first.