Origine: Fulani, West Africa
Source: Fulani/Fulbe oral-tradition proverb, documented in "Ten Fulbe Proverbs You Should Know" (nigerianpeoples.wordpress.com), consistent with the broader corpus discussed in "Proverbial Lore and Word-Play of the Fulani" (Africa, Cambridge University Press) — shepherd of frogs entry The source gives the saying with its own explanation: "a layman thinks they are all limping".
La source l’explique: a layman thinks they are all limping
. La formulation du sens est de nous.