What do you mean by a pig of

A pig of lead is a solid mass of lead, typically weighing between 40 and 90 pounds (18 and 41 kilograms). The term "pig" is thought to have originated in the Middle Ages, when molten lead was cast into sand molds that were shaped like pigs. The solidified lead could then be easily transported and stacked.

Pigs of lead are still used today, primarily in the manufacture of batteries, solder, and other lead-based products.

Pigs of lead were also historically used as a form of currency and were often stamped with the seal of the smelter or merchant who produced them.