The song "Beasts of England" and the poem "Comrade Napoleon" are both meant to serve a particular political purpose among the animals, but they have very different, even opposite, objectives.
Early in the story the animals hear "Beasts of England" for the first time. It is sung by Old Major. The purpose is to teach the animals something that will rouse their spirits and unite them in a cause that is larger than their individual selves, which is revolution against man.
The sixth stanza expresses the need to work for a better future:
For that day we all must labour,
Though we die before it break;
Cows and horses, geese and turkeys,
All must toil for freedom’s sake.
The song uses the words free and freedom once each, and every one of the seven stanzas makes some type of reference to the future and how things will be when animals wrest control of their lives from man.
The poem "Comrade Napoleon," on the other hand, is an attempt to inspire obedience and reverence for the leader of Animal Farm. Unlike "Beasts of England," there is no mention of freedom or the future or insurrection. This song, rather than rallying the animals to action like "Beasts of England," tries to establish Napoleon as worthy of worship. Part of Orwell’s intention is undoubtedly to show how religion is often used to control the masses in a society.
This religious flavor is created by giving the song an almost biblical feel: the words thee and thou are each used once. Napoleon is also called Lord and giver and compared to the sun. Finally, there is no mistaking the intent of the line:
Thou watchest over all,
As far as the ruling pigs are concerned, Napoleon is to seen as God by the working animals.
So, where "Beasts of England" urges animals to throw off their chains, "Comrade Napoleon" in essence asks animals to accept them and even love them.
Personally i think that "beasts of england" was a poem which concerned all the animals and they had only 1 motive- to fight for rebellion and "comrade napoleon" was a poem which would make the animals praise and cater only for the selfish napoleon who was not as hardworking and ambitious as snowball.