“In that,” said Gymnast, “he doth not resemble the foxes; for of the capons, hens, and pullets which they carry away they never eat the white.” “Why?” said the monk. “Because,” said Gymnast, “they have no cooks to dress them; and, if they be not competently made ready, they remain red and not white; the redness of meats being a token that they have not got enough of the fire, whether by boiling, roasting, or otherwise, except the shrimps, lobsters, crabs, and crayfishes, which are cardinalized with boiling.”
Throughout the book, Gymnast is giving teachings and lessons to the monk. This exchange is an example of how the author, Francois Rabelais, satirizes it.
In many parts of this book the monk learns and lives through what they learn, but in this example the words / teachings are not real/ are satirical.
The main focus of this exchange is to say that foxes don't eat the white meat of chicken because no cooks have prepared it. Stating the meat stays red and is inedible. While with shrimps lobsters crabs and cray fish, they do the opposite. They turn red when cooked instead of losing the red color.
The structure of this exchange is that of teacher stating something, then explaining through proverb why that is, or what is important about it. But within this book, that exchange does not make sense. The idea foxes don't eat chickens because they are red doesn't make sense, because foxes eat chickens.
The Idea shown by the Gymnast can be seen as "What one persons success looks like, would be another's failure." in the way of chicken being cooked is no longer red, while some seafood cooked is red. as if the two successes / triumphs looking opposite. This may be a valid view, but by starting this explanation saying something blatantly untrue satirizes the entire exchange.