Earlier quoted context omitted.
That difference between the literal word-by-word translation [1] and the semantic translation is my point of focus. In English, my suggested translation would be that “It isn’t worth it.” But since this word-for-word translation would feel unnatural (that is, it’s typically better to introduce « la peine » even if the word trouble/pain wasn’t in the original sentence), there can be an extra cognitive load that interr…
> Quand les poules ont les dents See "As rare as hens' teeth". Similar to "as rare as rocking-horse shit". My French is far from idiomatic; I hadn't come across "quand les poules ont les dents".
From Le Figaro [1]: « Précisons enfin que notre expression est un idiotisme et qu'elle ne possède pas, par conséquent, de stricts équivalents à l'étranger. Ainsi nos voisins anglais ont-ils l'habitude de dire «quand les cochons voleront», les Espagnols, de lancer «quand les grenouilles auront des poils» et les Allemands, de flanquer un «quand les poissons apprendront à voler». »
English translation: "Finally, let us specify that our expression is an idiom and that it does not, therefore, have strict equivalents abroad. Thus our English neighbors are used to saying "when the pigs fly", the Spaniards say "when the frogs have hair" and the Germans say "when the fish learn to fly."
[1] https://www.lefigaro.fr/langue-francaise/expressions-francai...