How are each of the Seven Commandments broken?

In Animal Farm, the Seven Commandments represent the animals' utopian dreams after they overthrow Mr Jones in Chapter Two. It does not take long, however, before the commandments are broken by the power-hungry and corrupt pigs. Here is a glimpse of how this happens:

1. "Whatever goes upon two legs is an enemy." This commandment is broken when Napoleon begins trading with the neighbouring humans, Mr Pilkington and Mr Frederick. In addition, by the closing scene of the novel, Napoleon has adopted human dress and walks around on his hind legs.


2. "Whatever goes upon four legs, or has wings, is a friend." Napoleon breaks this rule when he runs Snowball off the farm in Chapter Five and later portrays him as an enemy of Animal Farm. 


3. "No animal shall wear clothes." By the final chapter of the novel, all of the pigs can be seen in human clothing which they have taken from Mr Jones' wardrobe.


4. "No animal shall sleep in a bed." The pigs break this commandment in Chapter Six when they move into the farmhouse to be more comfortable.


5. "No animal shall drink alcohol." Napoleon changes this commandment to include the words "to excess" in Chapter Eight after he drinks whiskey for the first time and suffers from a terrible hangover.


6. "No animal shall kill any other animal." Napoleon breaks this commandment when he brutally slaughters the hens who rebel against him in Chapter Seven.  


7. "All animals are equal." This commandment is famously changed in the final chapter of the book when Napoleon declares that some animals are "more equal than others." This sums up the divide between the pigs, the ruling class, and the other animals on the farm.