How is the theme of collectivism demonstrated in Chapter 7 in the scene of the three farmers' pact?

When Bunce and Bean finally turn off their tractors at the end of a long day of futile digging for Mr. Fox, Boggis joins them. The three farmers are very angry at yet another failure and as a result, they make a pact never to let Mr. Fox go and they shake on their agreement. Collectivism is therefore depicted within the farmers' decision to work together to achieve their goal.