Final answer:
The irony in the pigs gaining so much weight is typically found in satirical or allegorical literature, symbolizing overindulgence and corruption, often of those in power. It can represent the transformation of the pigs into the entities they opposed, reflecting hypocrisy and the moral decay linked to the corruption of power.
Step-by-step explanation:
The question appears to relate to a satirical or allegorical work, where the irony of pigs gaining so much weight might point to underlying thematic elements such as gluttony, greed, or societal commentaries. In the context of a work like George Orwell's Animal Farm, for example, this would symbolize the pigs' transformation into the very humans they initially rebelled against, showcasing their hypocrisy and the corruption of power.
In literary contexts, pigs are often used symbolically to represent overindulgence and corruption. Thus, pigs gaining weight could be seen as a physical manifestation of their moral decay, especially if these pigs symbolize individuals or a class of people in power. This would correspond neatly with the common motif of the decadent ruling class in many satirical works.
Bringing in Nietzsche's parable of the lambs and the birds of prey, we can additionally highlight the thematic expression of the duality between oppressors and the oppressed, with the fattening of the pigs serving as a metaphor for the gain of the oppressors at the expense of the oppressed.