As I have stated on potty training threads many times before, potty training is really more for pee training than poo training because pigs will poo wherever they happen to be. So if you and other owners are getting frustrated because your pigs won't poo in the litter pan, then you may be expecting too much from your pigs. You really want the pigs to pee in the pan. Spot cleaning poos once or twice a day when using fleece is easy.
Well, my pigs will poo almost all the time, when I trained them before. Then they had like 5 accidents and I was tired of piclikng up poo. Anyways, thanks for hepling me.