Well Good Luck Muc
Only sharing true information from a major saddleback breeder in the North of Ireland, I believe Crab Apples were to blame according to their pig vet.
Not an experience I had, but then I would not feed a lot of one thing to my pigs.
Rare Breed pigs need handling carefully, and we have very few problems with all three breeds
we keep, the only problems we have had is with ones bought in, and that was a long time ago.
A varied diet is good for pigs and humans. We also suffer if we eat too much of anything too

Good luck with the bartering Muc - great to get it
Julie
