What do the pigs have to work on according to Squealer?

"There was, as Squealer was never tired of explaining, endless work in the supervision and organisation of the farm. Much of this work was of a kind that the other animals were too ignorant to understand. For example, Squealer told them that the pigs had to expend enormous labours every day upon mysterious things called "files," "reports," "minutes," and "memoranda." These were large sheets of paper which had to be closely covered with writing, and as soon as they were so covered, they were burnt in the furnace. This was of the highest importance for the welfare of the farm, Squealer said. But still, neither pigs nor dogs produced any food by their own labour; and there were very many of them, and their appetites were always good."