How did the pigs acquire another case of whiskey?

In George Orwell's "Animal Farm," the pigs acquire another case of whiskey by taking advantage of the humans' lack of oversight and their own cunning. After the initial supply runs low, the pigs negotiate with Mr. Whymper, the human solicitor, who helps facilitate the purchase of whiskey from nearby human farms. They justify their actions by claiming it is necessary for their leadership role, even as they increasingly indulge in human vices, ultimately betraying the principles of Animalism.