Meaning of "pig who sees the wind" in Byron's Don Juan

Question

From Byron's Don Juan:

Medals, rank, ribands, lace, embroidery, scarlet,
Are things immortal to immortal man,
As purple to the Babylonian harlot:
An uniform to boys is like a fan
To women; there is scarce a crimson varlet
But deems himself the first in Glory's van.
But Glory's glory; and if you would find
What that is -- ask the pig who sees the wind!
At least he feels it, and some say he sees,
Because he runs before it like a pig;
Or, if that simple sentence should displease,
Say, that he scuds before it like a brig,
A schooner, or -- but it is time to ease
This Canto, ere my Muse perceives fatigue.
The next shall ring a peal to shake all people,
Like a bob-major from a village steeple.

As I understand, the stanzas describe a pig that sees (feels) the wind and "he" (the pig) runs in the direction the wind is blowing. But what is the meaning of all this?

Why should a pig that feels the wind know something about Glory?

Answer 1

For a discussion of what Byron is saying here, see R.P. Lessenich's Romantic Disillusionism and the Sceptical Tradition:

It is in the service of such debauched monarchs and politicians, spoiled by luxury, located far from and virtually not even interested in the scene of action, that the soldiers risk their lives and vainly die in pursuit of immortality that glory will hardly confer on them. The soldiers promptly swallow the deadly bait laid out for them in the shape of an embroidered unform and medals... They see glory and run before it as pigs were proverbially ...

Apparently there was a folk belief or folk saying that pigs can see the wind. This is seen in line 1108 of Part 2, Canto III of Samuel Butler's 1684 Hudibras, with the line "As pigs are said to see the wind". (Footnote 139 of an edition of Canto VII of Don Juan pointed me to Hudibras.)

Google will lead to many occurrences, including an essay by Emerson, in YouTube videos and in the lyrics of Johnny Cash and in discussions of folklore. One occurrence is in a bizarrely bad anonymously written story "The Pirate and the Cruiser" anthologized in Marguerite Gardiner, Countess of Blessington's The Honey-Moon:

The crew laughed at Peter's prophecy; but it was not such a hearty laugh as was the general custom. That pigs see wind was not altogether disbelieved, and that the pig's snout was pointed right ahead was beyond a doubt.

It's a small world: the anthologist knew Byron, having met him in 1823, soon after Canto VII was written, and wrote a book about him. The story itself seems to have first appeared in the United service journal, and naval and military magazine; October, 1836.