Whole grain will pass straight through them without being digested, so they won't get any sort of feed value from it and if it's mouldy you run the risk of your pigs getting ill - there were a few cases of pigs dying after eating mouldy pig food a couple of years ago. Not worth the risk in my opinion, especially if you have to end up paying vets bills or losing any of your stock.
But others will maybe disagree with me ?
Karen