What is the Hierarchy in Animal Farm?

The animal rankings in the book goes as follows:

Napoleon>Squealer>Humans>Other animals.

As you can see, Napoleon worked himself up to the top with rumors, propoganda, and lies. He represents Stalin. Squealer, who represents Lenin, is his ever faithful lackey and helps him to spread his propoganda, lies, and rumors. The humans represent the richer folk in Russia at the time, being equal but at the same time not as equal as Stalin. And the other animals represents the working class, the peasents, and the regular citizens.