what techniques in chapter 7 + 8 does Napoleon use to make the outside world believe everything is going well? What is really happening?

In Chapter Seven, because of increasing food shortages, the animals begin to go hungry. Knowing that the humans must not hear of Animal Farm’s hardships, Napoleon enlists the sheep to comment about their increasing rations when within earshot of Mr. Whymper. He also has someone lead Mr. Whymper past the food bins, which are filled with sand and topped with grain to look full.