There are a few examples of "murió estirando la pata" in Google but not many, and it doesn't make sense to my non-native ear. "He died kicking the bucket"? Sounds redundant at best. Did you hear someone say it? Can you provide us context please?
Yes, someone told me in Costa Rica that morirse estirar la pata is like when someone drops dead on the ground, like from a heart attack or something, but I was just confused if you use the whole phrase together. But I think you've answered my question well enough. Muchísimas gracias.
Literally, "estirar la pata" means to "stretch a leg out." Whenever I hear the phrase I think of a cartoon character falling over on its back with its legs stiffly stretched out. AKA "kicking the bucket" or "biting the dust" or "falling over dead." I agree with aldonza I've only ever heard it used on its own.
Sounds like overkill to me. ( ) I've certainly never heard both "morirse" and "estirar la pata" used together in Spain.
Incidentally, there is also "la palmó" (he died, croaked, cashed in his chips, etc.).