It is a Madrid expression for a good meal, from which the cook hides the ingredients, because he wants to keep the secret of his recipe, or because he considers impertinent a query that he does not want to answer. It seems to come from a popular game in some festivities where a rooster was hung from a rope and blindfolded participants tried to beat him to death, and whoever got it took it to cook it with rice, although in some cases it was shared with the rest of the partygoers. For the latter is that this locution is associated with banquets and popular celebrations. See dead, "canguingos and fish legs".
