What is foreshadowed when Squealer tells the animals they will eventually learn that Snowball's heroism in battle was "much exaggerated"?

With Squealer, Orwell is foreshadowing that eventually anything and everything will blamed on Snowball.  Squealer apparently realizes that the animals have short memories and often question their own memory when they are told differently.  At the point where Squealer states that Snowball's heroism will come to be seen as exagerrated, he knows that he cannot say a lot at that moment because the animals remember seeing Snowball grazed by the gun shot by the farmer.  While he cannot erase that memory, he knows that time is on his side and that he will eventually be able to get the animals to see history the way he wants them to see it.