Fredhatt's poem takes the things we find disgusting, manure and rotting corpses, and insists they are the source of everything good. The opening sets up the idea: we recoil from them, yet they are a "horn of plenty." From there the speaker argues that new life always grows out of old life's remains, helped along by beetles and worms that break the dead body down.
The speaker sounds blunt, half joking and half serious. Asking "How hard can it be?" to love the smell of healthy manure, when we already put up with polluted kinds, gives the poem a wry, teasing edge. Underneath the crude language, though, there is real respect for the cycle of death and renewal. Birth is a chance for change, death a reckoning.
The mood is earthy and oddly cheerful. The final list, "ever renewed, ever fresh, ever aging, ever stinky," refuses to clean life up. It accepts the glory and the smell together.