The idiom fox guarding the hen house goes back at least as far as the 1580s. We will examine the definition of the phrase fox guarding the hen house, where it came from and some examples of its use in sentences.
The fox guarding the hen house describes a set of circumstances in which someone who should not be trusted has been chosen to protect someone or oversee a situation. The choice involves someone directly unsuitable for the task, such as choosing a bank robber to guard a bank. The idiom the fox guarding the hen house is also often used to describe someone who is put in charge of policing himself. For example, allowing an industry to make and enforce safety rules with no oversight by a government entity is a situation in which the industry has a vested interest in not pursuing safety with vigor. This is an example of the fox guarding the hen house. The earliest known use of this sentiment is found in The Contre-League and Answere to Certaine Letters Sent to the Maisters of Renes, by One of the League who Termeth Himselfe Lord of the Valley of Mayne, and Gentleman of the Late Duke of Guizes Traine which was published in 1589: “…he is a wolfe to keep the sheep, and a foxe to looke to the hennes.”
“When you have a home team in charge of the official book,that’s like the fox guarding the hen house” Troy Allen, who last week resigned as State College coach, said in June. (State College News)