What dealing does Napoleon have with Fredrick & Pilkington?
Their first interaction comes when Pilkington and Frederick lead a group of farmers to try to retake the farm from the animals in the Battle of Cowshed - the animals defeat the humans and celebrate their victory. Later, Napolean decides to begin trading with the humans, even though they are supposed to be viewed as "enemies" according to Animal Farm's commandments. He first decides to trade timber to Pilkington, but then changes to Frederick, who tricks him by giving him forged banknotes. The pigs also get a lot of whiskey from the humans and discover they like it, even though another command says no animal is to drink alcohol.
Frederick later leads another attack on the farm and blows up the windmill. In the final chapter, Napolean shows Pilkington around the farm, and P. is impressed by how little food the animals on the farm are given yet how much work they do. He says he will implement some of these practices on his own farm. N. then announces he will rename the farm "Manor Farm" - its original name - showing how things have come full circle. In the final scene, both P. and N. play the ace of spades in their card game, proving they are both cheating, and the animals outside look from man to pig and realize they are unable to tell the difference.
There is another incident in Chapter Seven in which Napoleon finds a pile of timber and instructs Mr. Whymper to sell it. Pilkington and Frederick are both "anxious" to buy the wood, and Napoleon spends some time deciding to whom he should sell. In the next chapter, Napoleon decides to sell the timber to Frederick, but Frederick pays for the logs with forged banknotes. When Napoleon realizes what has happened, he is furious and pronounces the sentence of death upon Frederick. Frederick and his men then attack the farm and blow up the windmill.
This scene is reminiscent of the Non-Aggression Pact, which Hitler and Stalin signed in 1939. It was a great surprise to the world that these two great powers would sign such a pact, just like it shocked the animals to see Napoleon sell the timber to this enemy, Frederick. Two years after signing, Hitler broke this pact by invading the Soviet Union, a move represented in the story when Frederick pays for the timber with forged money and then attacks the animals' farm.