Ithink the author implies the main idea rather then directly stating it because
i don't know how to answer this question i know you didn't read harriet tubman ( guide to freedom) but in general how would you answer this with any story.
me

normally working animals are domesticated and ruled by a master, a domesticator (tamer), to perform basic and important functions on a farm, for example. the value used in this context is animal labor in exchange for food. it is not so much a contrast to the story told by napoleon and the pigs, since the animals of that particular farm also performed functions on the farm through domestication. the only thing is that in this case, who rules them is a pig, also an animal, but very respected, to whom the other animals lent him submission. that's about a strong relationship of dependency between animal and owner.

never read it so if i had i would definitely you sorry.