Ive found it to be true. They are rather prolific. A sow can start having pigglets in a matter of months after birth. I think either just before a year old, or a little after on year of age. They can also have two litters a year, and litters up to 16 pigglets. On my land they are everywhere. Out at my lake cabin, there use to be no signs what so ever of hogs. In the last 9 years I started seeing signs of them and now the lake is eat up with them as well.