Cats can catch mice as well as chickens. What are the main contradictions and subdivisions here?

This is a short fable in Liu Ji's "Yu Lion Mouse Catching".

Cats can catch mice and chickens.

The main contradiction is the plague of rats. Rats eat food, destroy clothes, gnaw furniture, and dig holes through walls. They do all kinds of evil. They can also transmit plague and bring disaster to people.

Catching chickens is a secondary contradiction: if you catch all the chickens, the worst thing you can do is stop eating chickens in the future, and it won’t affect your life.

After weighing the pros and cons, it is better to resolve the main contradiction.