Most poems about coming in from the cold would linger over the fire. Edward Thomas gives us the food and warmth in a single line, then lets something else take over: a bird's cry from outside. «The Owl» is about a man who has earned his comfort, enjoys it, and cannot enjoy it cleanly, because the night still holds people who have no inn to walk into.
The first stanza is built around the word "yet". The walker is "hungry, and yet not starved; / Cold, yet had heat within me that was proof / Against the North wind". Every hardship is measured and then qualified, so he sounds like someone who knows exactly how much he can bear, and how much worse it might have been. "Proof" is a word from armour-making, and it makes his body sound like a small fortress. The second stanza answers the three complaints with three comforts, "food, fire, and rest", and repeats the list in a slightly twisted grammar: "Knowing how hungry, cold, and tired was I". Needs and satisfactions line up like a balanced ledger. Then the owl arrives and spoils the sums.
The form is quiet. The lines move in loose iambic pentameter, close to the rhythm of someone thinking aloud, and the sentences spill across stanza breaks. "All of the night was quite barred out except / An owl's cry, a most melancholy cry" runs on into "Shaken out long and clear upon the hill", so the sound slips over the gap between stanzas just as it slips past the shut door. The colloquial "quite" and the door image ("barred out") make the safety feel solid, which only makes the intrusion more striking. The rhyme is just as restrained. Only the second and fourth lines of each stanza chime (proof/roof, I/cry, merriment/went, voice/rejoice), and some of those are near-rhymes. You hardly notice the pattern, but where it lands it matters. "I" rhymes with "cry", as if the traveller and the bird were answering each other. The last pair, "voice" and "rejoice", pulls the owl's call and the denial of joy into the same sound.
The third stanza strips the owl of any cheer: "No merry note, nor cause of merriment". The negatives pile up flatly, and "Shaken out" makes the cry sound either flung like cloth from a window or trembling with cold. The bird is a plain-speaking messenger, "telling me plain what I escaped / And others could not". "Escaped" is the key verb. It turns the night into a danger and the inn into a refuge, and it admits that the speaker's luck was only luck.
The final stanza turns on "salted". The food and the rest are "Salted and sobered", and the repeated "s" sounds seem to hush the line. Salt suggests seasoning, but also tears and bitterness. Nothing is cancelled, since he still eats and still rests, but the pleasure is altered, like a drink that has been watered down. The owl speaks "for all who lay under the stars, / Soldiers and poor". "Lay" is deliberately open. It could mean people sleeping rough, or it could mean something more final. Soldiers and the poor are joined by being outdoors through necessity rather than choice. Thomas was himself killed as a soldier in the First World War, which gives that word extra weight for a modern reader, though the poem works without it.
The poem is significant for what it refuses to do. It does not reproach the speaker for being warm, and it does not let him settle into complacency. The owl does not get a sermon or even a consoling last line, only the flat phrase "unable to rejoice". Thomas trusts a small human moment, a tired man at a table hearing a sound through the wall, to carry a large idea: comfort is more honest when it remembers who is still outside.