In burying the hams, the animals are paying tribute to their former comrades. The pigs were slaughtered for their meat, just one of the many examples of animal exploitation which the Animalist revolution is determined to sweep away. All revolutions need their martyrs, those brave souls who lay down their lives for a noble cause. The burial of the hams is a deeply symbolic ritual which galvanizes the animals, uniting them in a public act of remembrance.

The Animalist revolution isn't just political and economic; it has a moral dimension, too. The consumption of alcohol is regarded by the animals as a sign of the decadence and moral corruption of the hated human oppressor. So it's not surprising that the animals empty the beer barrel; it's a symbol of what they're fighting against.

They bury the hams simply because they are the remains of former comrades, and while Orwell doesn't elaborate on their intentions, it seems that they just want to pay them proper respect. Boxer destroys the beer barrel probably because the animals associate alcohol with the laziness and cruelty of Jones, who was often drunk. In fact, he was drunk when the revolution broke out in the first place. The animals thus have a particular aversion to alchohol, which is reflected in their fifth commandment: "No animal shall drink alcohol." Taken together with their destruction of the whips, harnesses, and gelding knives, as well as the ribbons that horses wore in their manes, it seems that the animals are intent on fulfilling the tenets of Animalism by destroying all of the corrupting and oppressive influences of humanity. The farmhouse itself is to be left undisturbed as a museum to their former lives.