Alectryomancy

Meaning: divination by rooster, usually by interpreting patterns in how they eat grain. Cotgrave:

Divination by a Cocke; or by the Cocke stone. 

Usefulness: 1 (If you can't make a joke out of that, you shouldn't be reading a blog featuring Rabelais. Otherwise I suspect it'd only be useful if you have roosters, unless you try the same technique with gulls or pigeons: you could assign pieces of bread certain values and see what order they were eaten in. "I tried alectryomancy* with gulls at the lake today; apparently you should look for a new job in February.")

Logofascination: 2 (From the Greek for cock. Also known as alectromancy.)

In the wild: Not really; wikipedia mentions some of the rules, and a few alternative forms.

Degrees: 1

Connections: n/a

Which is used in: G&P, Book the Third, XXV: The -mancy chapter.  Twice, even, and Rabelais helpfully gives instructions on how to carry it out:

Or yet by alectryomancy. If I should here with a compass draw a round, and in looking upon thee, and considering thy lot, divide the circumference thereof into four-and-twenty** equal parts, then form a several letter of the alphabet upon every one of them; and, lastly, posit a barleycorn or two upon each of these so disposed letters, I durst promise upon my faith and honesty that, if a young virgin cock be permitted to range alongst and athwart them, he should only eat the grains which are set and placed upon these letters, A. C.U.C.K.O.L.D. T.H.O.U. S.H.A.L.T. B.E. And that as fatidically*** as, under the Emperor Valens, most perplexedly desirous to know the name of him who should be his successor to the empire, the cock vacticinating**** and alectryomantic ate up the pickles that were posited on the letters T.H.E.O.D.

Apologies for the very late post; Friday's post will happen over the weekend sometime. In the meantime, I offer you the bonus word of pullularius, the keeper of the chickens, a useful word if ever I saw one. 

*laridaemancy?
**the alphabet was shorter: no J, U or W, but probably included & as a letter.
***relating to prophecy.
****prophesying.