Consider the following food chain.

grass → caterpillar → chicken → fox

What role does the chicken play?

I said secondary but i could be wrong

The role of the chicken is to prevent caterpillars from spreading too much, and its role is also to get eaten by the fox. This is how the food chain works and upsetting it would upset the balance of the nature. The fox will get eaten by someone else then and we will eat that someone else or use them for something, and when we die the earth will take us and grow plants and plants will get eaten by caterpillars, and so on and so forth.