In Bereshit 29 we learn that Rachel was shepherding her father's sheep. Do any commentaries explain why Rachel, the younger sister, was the shepherdess instead of Leah the older sister?
Ramban there offers a couple of reasons:
Leah's eyes were weak (29:17), so the sun would be harmful to her.
Precisely because she was older, so there was more of a concern that the shepherds would take inappropriate liberties with her.