The Leoric’s Shinbone is by far the easiest item to find for the Secret Cow Level. First, at the character screen, click Change Quest.
Under ACT I Chapter 9: The Imprisoned Angel, select The Cursed Hold.
Click Select Game. Walk to the New Tristram Waypoint and search under The Highlands. Select Leoric’s Manor.
You will spawn at the back of the Leoric’s Manor. Walk into the ritual room and move toward the front of Leoric’s Manor. The room to the east has a fireplace with a big painting of Leoric’s face. It takes a few random games to see the Burnt Logs inside the fireplace.
Click the Burnt Logs to loot the Leoric’s Shinbone. It’s one of the materials needed to get access to the Secret Cow Level in Diablo III.
This is the Leoric’s Shibone Tooltip.