First of all, the salt kills all the harmful bacteria. I don't know how true this is, but it's said that mammal meat is denser than poultry meat, bacteria can't

First of all, the salt kills all the harmful bacteria. I don't know how true this is, but it's said that mammal meat is denser than poultry meat, bacteria can't grow inside of it (or at least have a lot more difficulty growing inside. Duck prosciutto is a thing too though, so maybe it's just chicken?