What happens to Slim's dog and her puppies? What does this tell us about survival as a migrant worker?

Slim's dog and her pups stay in the barn. He gives one to Lennie (which is smothered), and he offers one to Candy. When they were born, Slim drown four out of the nine right away because she couldn't feed them. This event shows us that migrant workers don't attach themselves to anything. They're loners.

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