Mantic is good about putting rules up for free on their website. That way, you get a look at what you're getting into when you put down your money for figures. As I've mentioned before, I think it's a wonderful idea. They continue in that tradition with the release of their rules for The Herd, a new Kings of War faction.
The Herd is going to be coming out in the Uncharted Empires expansion book, slated for a November release. This book will contain rules for League of Rhordia, Ratkin, The Brotherhood, The Empire of Dust, Reptilians (looking forward to this one, myself), The Herd, The Varangur, and two other still-secret factions. The Herd joins the Ratkin as downloadable rules sets. Go check 'em out.