From the beginning, the animals were too trusting of the pigs. The pigs were underhanded and when they were about to get caught or got caught, they were able to use their rhetoric to make themselves look good or get their way. Had the animals pressed the pigs, they would have seen the injustice of the pigs.
The first clear instance of this point is when the milk disappeared. The animals discovered that the pigs took it. Here is what the text says:
The mystery of where the milk went to was soon cleared up. It was mixed every day into the pigs’ mash.
The pigs, of course, explained this away. They actually did not like milk or apples, but science has proven that milk and apples were necessary for the pigs for their health. So, by taking the milk and apples, the pigs could use their brains to keep Mr. Jones away. The animals just accepted this, rather than challenging the pigs.
Later the pigs changed the commandments. Here is what the text says:
‘It says, ’No animal shall sleep in a bed with sheets,” she announced finally. Curiously enough, Clover had not remembered that the Fourth Commandment mentioned sheets; but as it was there on the wall, it must have done so.
Again, the text says:
They had thought the Fifth Commandment was ‘No animal shall drink alcohol,’ but there were two words that they had forgotten. Actually the Commandment read: ‘No animal shall drink alcohol to excess.’
Once again, the animals did not press the pigs for an explanation. They just accepted it. Had the animals challenged the pigs, things may have turned out differently.