Why were the animals so afraid of Frederick in "Animal Farm"?
Mr. Frederick is first described as "a tough, shrewd man...with a name for driving hard bargains" (Chapter IV). As the animals have increasingly frequent dealings with him, they find him to be ruthless, unreasonable, and unyielding. Eventually, rumors abound that Frederick and his men are plotting "to attack Animal Farm and to destroy the windmill". It is said that Frederick "has already bribed the magistrates and police" to clear the way for himself to overrun Animal Farm and take it over.
What really frightens the animals about Mr. Frederick, however, are the stories circulating "about the cruelties (he) practice(s) upon his animals". It is said that
"He flogged an old horsed to death...starved his cows...had killed a dog by throwing it into the furnace...(and) amused himself in the evenings by making cocks fight with splinters of razor-blade tied to their spurs".
The thought of such a depraved individual plotting to invade their community fills the animals with terror and rage (Chapter VIII).
In the allegorical message of "Animal Farm", Mr. Frederick is meant to represent Adolf Hitler. Like Hitler, Frederick is treacherous, violently attacking the Farm and destroying the windmill after signing an agreement of cooperation.