One of the main morals is about the corrupting influence of power. In Animal Farm, the pigs who gain power gradually become as bad as the human oppressors they overthrew. It shows that those in power can easily abuse it for their own benefit.
Another moral is the danger of a naive and unquestioning following. The other animals in the farm blindly follow the pigs at first, believing in their leadership without really thinking about the consequences. They don't realize that they are losing their own rights and freedoms until it's too late. This tells us that individuals should be critical thinkers and not just follow leaders blindly.