Snowball was hailed a hero after the Battle of the Cowshed and was even awarded for his efforts. However, it is not sustainable and he loses ground against Napolean who, through Squealer's efforts with the sheep, is able to have Snowball heckled during crucial moments in his speeches and in particular when he is exiled from the farm :
the sheep break into chants of “Four legs good, two legs bad,” at the most crucial moments of Snowball’s speeches.
Napolean and Snowball each present their vision of the farm - quite different from each other. Napolean is passionately opposed to Snowball's idea of the windmill and attempts to confuse the animals. When he realizes that there is a strong possibility of the animals voting with Snowball, he creates a scene and screeches whereafter
nine enormous dogs rush in and chase after Snowball.
Snowball has no choice but to run and is seen hurtling through the fence and is never seen again, although he is blamed for sabotage and accused of collusion in his absence. He has unwittingly given Napolean plenty of opportunity to lie and use him as a scapegoat to further his own cause - with the help of the persuasive Squealer.