As I wrote below, I have trouble approaching the Renard cycle looking for a "moral" to the story, or "good" and "bad" characters worthy of our praise or rebuke. This is a text where the winners cannot easily be distinguished from the losers. Instead of trying to extract a lesson from the story that may not even exist, one alternative way to approach the cycle is to look for a theme that may appear in the text in a variety of forms, not with moral justification or judgement, but simply as exempla of a phenomenon at work. With this strategy in mind, the topic of speech leaps out to me as a very important factor throughout the stories, one that receives multiple treatments as the text progresses.
While it is true that the physical, one might say slapstick, humor of the cycle has its part, much of the action and humor is driven by the character's dialogue. This, of course, is already placed in the absurdist context of predators and prey "negotiating" with each other for dominance by the skill of their tongues, rather than the strength and speed of their bodies. In no place does Bruin the bear or Ysengrin the wolf "win" because of their superior strength—the one exception I can think of is Renard himself, who seems to be rather quick on his feet and capable of outrunning the angry hordes who set out for his head. If question of physical strength is, in this system, a relatively moot point, I find it interesting that Noble the lion is king; is there a subtext that problematizes the very basis for his legitimacy at work?
Whatever the case, most of the tricks, plots, and deceits revolve around who is able to speak and guide the interpretation of a set of events. Take the affair between Renard, Hersent, and Ysengrin. Renard is able to "seduce," or at least persuade, Hersent into sleeping with him through his words—and not just words about himself, but through his manipulation of reported speech! He is able to create a reality in which their affair is perfectly justified. When Hersent's infidelity is discovered by Ysengrin, her only way out, as the narrator himself admits, is to "give him the answer he required" (II.1191). She is successful in this: Ysengrin is speechless ("Ysengrin doesn't know what to say," 1205), effectively neutralizing his ability to say what really happened, to be the articulator of the truth. In the second encounter between Renard and Hersent, the power of words is pitted against the testimony of an eyewitness, usually considered incontrovertible. In a case where visual evidence should be all that is required, Renard is able to cast doubt on its reliability: "Not everyone, my lord, agrees; / The way you see it is just not right" (1328-29). Ysengrin, understandably, retorts, "Do you think that I have lost my sight? / That I haven't any eyes in my head? / How on earth could I be mislead" (1330-32). With his clever explanation, Renard is able to get away and put the onus of guilt upon Hersent, who is only able to diffuse her husband's anger when she herself is able to speak at the beginning of Branch Va (l. 284). Right before this scene, Renard says something rather interesting to Hersent: "You said I liked to boast. / And I won't have you made a liar! / To tell the truth is my desire" (1290-92). This kind of verbal alchemy, to turn speech into truth, seems to be the real weapon of war in these tales.
The episode between Renard and Chanteclere is an interesting reversal of this fixation on speech. Renard is able to trick Chanteclere by telling him how much he wants to hear his voice; Chanteclere is later able to free himself by goading Renard into taunting his pursuers. Both deceits are carried out through the act of opening the mouth to speak, which may be why Renard muses at the end, "May he, for shame, never raise his head … he babbles when he should keep still" (II.446-8). Chanteclere's inability to properly interpret his dream, and his refusal to listen to his wife Peinte's justified words of caution, show that the ability to discern the valid interpretations from the misleading is not just an art form; it is a fundamental skill for ensuring one's survival in this world.