The connection between Popeye’s physical strength and his consumption of canned spinach has become a pop culture touchstone, with the reference remaining readily recognizable even nearly a century after the character’s debut – except surprisingly, the legendary brawling sailor’s strength came from a very different source in his first appearance. Instead of leafy green vegetables, Popeye powered up by…rubbing the head of a hen?

https://screenrant.com/popeye-strength-spinach-backstory-hen-factoid/