The poem is an extended metaphor whereby Hughes uses the mysteroius, wild and unpredictable fox as a comparison with the poet's writing process.
There is tension and anticipation in the blank snow outside the writer's window and the blank page in front of him. The notion that there is 'something more near' grasps the attention of the reader and the writer.
The fox - like the idea - remains indistinct though clearly felt and anticipated due to Hughes' ability to arouse the senses. The enjambement used between the third and fourth stanzas serves to speed up the pace of the writing, the animal and the idea which is being formed.
The opening lines of the final stanza condense the metaphor fully as the idea and the fox become one-
Till, with a sudden sharp hot stink of fox
It enters the dark hole of the head.
The idea and the writing produced remain as independent and unique as the fox itself-
Coming about its own business
This image serves to remind us of the wild unpredictability of the creative muse of the writer and the untamed spirit of pure poetry.