young pig
豵 centers on a young pig, specifically a piglet or small pig.
豵 combines 豕 (pig) with 從, which likely contributes the sound. The character is used specifically for a young pig.
The left side 豕 is a pig, and the right side 從 suggests following or accompanying. Picture a young piglet following closely behind its mother: 豵 is a young pig.
For ソウ, imagine a young piglet making a soft 'sow' sound as it follows its mother: sow -> ソウ.