different litters like different things it seems. My first litter 5 years ago cleared a 2 acre field that was entirely nettles ... this left a vacancy for the thistles though
... last years litter didn't go after them, though Charlotte their mum did. There are no nettles in the pig field where they now are and they chomp through the wire to get at the nettles in the field next door.
I also feed nettles to my horse, having waited a couple of hours for the sting to go out.... I look a right mad old bat. me at night on the common, arms full of cowslips for the horse, nettles for the horse and nettles for the pigs ... ah well, we weren't all made to be elegant and beautiful