"Man is the only creature that consumes without producing." How does Old Major prove this in Animal Farm?

Old Major is pointing to the fact that the animals do all of the work on the farm but reap none of its benefits. This was also a key idea of Karl Marx, who wrote helped write Communist Manifesto. Marx's point was that workers should be able to share in the fruits of their labor. Old Major is making a similar point that the animals should be able to share in the profits from the farm. Instead, Jones takes all the profits and makes the animals (his workers), do all the work and doesn't even feed them properly.