Lanchester’s laws are mathematical formulae designed to calculate the relative strength over time of a predator and prey pair. They’re usually used for military modelling. In this case, even one loss can lead to more losses over time.
The pigman depiction of orcs apparently derives from Ludovico Ariosto’s Orlando Furioso, where they had piggish features. Other depictions include the original corrupted-elf Uruks by Tolkien and the Warhammer greenskins. It seems Maruyama has decided to make them full-on pig beastmen. No, this is not a translation of the CN TL note below.