What you'll find is that pigs are very much like us - they have their likes and dislikes. Most of mine love carrots, for example, but two will just leave them to rot. Broccoli is a huge hit with two of the herd, but the others will just pick at it or kick it around.
As mentioned earlier, whatever you give (and, of course, according to the regulations), just don't overdo it. Feed fruit and veg as extras, not as a partial substitute for standard feed.