We bump into some in the 300 lb. range, but we are hunting free range so it takes a bit of work. What we do have is some superior old genetics and the Razorbacks on them are awesome. Real tall mohawks on good sized pigs. If you consistently use Sow in Heat, you'll eventually attract the biggest you have, whatever that might be, but we don't have any real strong domestic crosses to get them to that 500 - 600 lbs size.

I did try cracked corn, but it seems to do the same thing. I don't have any moisture getting in and I no longer use additives, but I haven't tried the sand trick. That sounds pretty good.