Only short-sighted and unwise bosses would hold their employees to a far-fetched standard that might shoo them away. この表現は自然ですか？

There's nothing really wrong with it, but some of the vocabulary choices feel just slightly off.

Far-fetched is passable here, but it's usually used more for things that are not believeable, so I'd probably just say something like "unrealistic" in this context.

"Shoo away" seems like something a busy mother would do with children getting in her way. It comes across as someone intentionally trying to make someone go away, but somewhat ineffectually. A better choice of phrase here would be "drive them away."