PUSH THAT COW, DO IT NOW!
A full set of Herd-A-Balls at a lower price than purchasing separate packs!
The Herd-A-Balls are intended for livestock herding games and built to be pushed around. A physics prim that bounces around is much less laggy and harder to break than a scripted animal. ( I did not come up with the idea originally and I don't claim it as my own invention. )
These have a lightweight script that lets them turn and slide freely using SL physics, but prevents rolling upside-down. This makes it easier to see labels for games where they matter, and adds a little bit more realism. (...But not that much, I lack the scripting chops to make them face the direction they are "running", sorry!) Because they don't roll, a prim at the top can be used to add labels to them for your games.