What is the main theme of "The Fox and the Goat"?

Well to find the theme yourself you would want to look to see what the author was asking the reader or what message the story is telling the reader.

But, if you're looking for an answer exclusively, I believe the theme is along the lines of selfishness and the true nature of the human heart. Another interpretation of the theme would be to Look Before You Leap, or not be too trusting of others.

It's basically telling you to look before you leap. They always have morals