Crow Communes is a parody of the Christian rite of communion, where the celebrants consume bread and wine and believe that it either represent or mystically becomes the flesh and blood of Christ. In the poem Crow literally eats a piece of God.
The Crow poems are a cycle, and it's worth considering what has come before this ghastly communion. God has been trying to teach Crow to be more human, to understand love. The result is merely horror, symbolic of religion's failure to elevate humanity to peace and contentment. God has given up and is asleep at the start of this poem.
In this context, then "under hearing beyond understanding" attempts to describe the metaphysical nature of what Crow is attempting to gain. Religious insight cannot be taught - it is "beyond hearing". And, like most mystical experiences, it is based on sense and emotion more than logical comprehension - it is "beyond understanding". Instead of rationality, Crow's communion reveals a more sentimental insight.
"What is happening to crow" is that he has, finally, gained some of the insight that God was trying to teach him (futilely - see above) in the previous poems. It is, however, of limited use.
After the revelation crow is described as a hierophant:
a person, especially a priest, who interprets sacred mysteries or esoteric principles
It's worth noting that this interpretation will occur through a flawed human vessel. Then Crow is "impenetrable", only "half" illumined, "speechless" and, in the next line "appalled". The implication is that for all the divine insight Crow has gained, he can do nothing useful with it. It's incomplete, incommunicable and actually very worrying and dangerous.
Later poems in the cycle hammer home this theme. In Crow's Theology he uses the divine insight to imagine his own God, who is:
much bigger than the other
Loving his enemies
And having all the weapons.
In other words, one who is tragically flawed and created in Crow's own lust for power. Later is Truth Kills Everybody in which crow is symbolically "blasted to nothing" by the knowledge he has obtained. Learning, in other words, has the dangerous capacity to destroy the self and rebuild it anew.
Let's return to the word "humped" because it's a really interesting choice. At first sight, it's not obvious how it's relevant to the message of the line. One thing it does achieve is a metrical disruption, balancing a subject against a predicate, making the line stand out to the reader.
Still, other words could be used to the same effect. So, why "humped"? I have no references for these suggestions, but it occurs to me that it could be because of the multiple meanings behind the word. In the initial reading, "humped" suggests a mound of flesh, an image that crow has literally become bigger and stronger.
In British slang, however, it can also mean a bad mood - someone can "have the hump" when they are angry or depressed. So it's indicative that Crow is beginning to regret his meal, a foreshadowing of the "appalled" with which the poem ends.
It also has another slang meaning, though, which is the sexual act. The whole Crow cycle deals with the act of creation: of the universe of crow himself, of crow's understanding of the world. Crow's new insight is, in some ways, an act of creation itself and he'll later use it to "create" his own theology. So the insertion of a word that can be read as the human equivalent of creation seems fitting in the context.
References:
- Al-Husseini, Sahar. (2010). Animal Imagery in Ted Hughes' Poetry.
- Radin, P., The Trickster, NY, Greenwood, 1969
- Twentieth-century Literature in Retrospect, ed Reuben Arthur Brower
