I *finally* got around to introducing Pinky (our first pig; spayed sow about 2.5 yrs old) to the Terrible Two (Toad & Truffle; 6 mo barrows). They have lived in adjacent pens (ok - with a small rabbit pen in between) for several months ... but the time had come to let them co-habit.
I relocated the rabbits, and removed the barrier btw the pens. This kept each of their sleeping areas the same, and I left food and water in their respective ends of the now L-shaped pen.
Thankfully, all went well ... Pinky ran them down a few times, and there was much squealing. But the boys are smaller, faster, and there are two of them ... so it was all pretty normal. It will be a while until they become friends, but I am hopeful that they will eventually become buddies.
Keep you posted!