A herd of pigs is called a drove or sounder and sometimes a herd of pigs is simply called a herd of pigs.
Although drove and sounder are also terms that a herd of pigs are called.
For a young herd of pigs, the young herd of pigs is often called a litter or drift and even drove of pigs.
Older pigs are often called a sounder and a group of hogs are often called a team or passel.
Although herd is a general term that is often used for domesticated pigs.
Drove/Drift is often used for younger pigs or for pigs that are being moved.
Sounder is commonly used for a group of wild pigs or swine or older domestic pigs.
Age specific terms when referring to a herd of pigs include.
Singular which is a group of adult male pigs or boars.
Litter which is a group of piglets that are born to the same mother pig.
Passel and Team can refer to a group of hogs, especially when working or moving together.