Oh poor piggies, I hope they're ok. When my rabbit got out, the second night I had him, I couldn't catch him so had to let him find his own way back to his hutch. I sat inside watching quietly and when he went in I ran up and shut the hutch.
If they are tame enough then maybe you can put down veggies and see if they come over. If not, I'd put down their run, with veggies inside and watch from inside to see if they go back in.
I really hope you find them.