I think that the way the characters are introduce reminds me a lot of ‘Tom and Jerry.’ Which I think could of been based a lot on the characters personalities.

Napoleon:

‘Napoleon was a large, rather fierce-looking
Berkshire boar, the only Berkshire on the farm, not much of a talker, but
with a reputation for getting his own way.’

This small extract reminds me a huge amount of the big dog in ‘tom and Jerry’ that looks after Jerry most of the time.

Squealer:

‘…with very round cheeks, twinkling eyes, nimble movements, and a
shrill voice. He was a brilliant talker,’

Squealer reminds me a lot Jerry as he is the smallest and cutest. He is a good talker just like Jerry is because Jerry usually convinces the Dog to fight against the Cat.

Snowball:

‘Snowball was a more Lively
pig than Napoleon, quicker in speech and more inventive, but was not
considered to have the same depth of character.’

This is probably not the strongest but I would connect him to Tom. Although Snowball does not try and eat squealer, he does always get into fights with Napoleon.