Does a hen need a flag?

The Running Manから今日取り上げるのは単語ではなく、慣用句とも言えないような表現です。
“Ben Richards?” He used no bullhorn, and without it his voice was soft and cultured without being effeminate in the slightest.
"Yes.”
"I have a sworn bill from the Games Federation, an accredited arm of the Network Communications Commission, for your apprehension and execution. Will you honor it?”
"Does a hen need a flag?”
何でこんな所で鶏のことが出てくるのか不思議です。 "hen need a flag" を含む慣用句を探しましたがありそうもありません。結局Google検索で次の記事を見つけました。
When people want something they don’t need, you sometimes hear them say they need it like a hen needs a flag. Hens aren’t particularly in need of flags and obviously the useless of the need is why the expression exists. However, tracing back the history on this idiom proved almost impossible.
なるほど反語的な表現ですね。Googleで更に調べると、この表現 "You need that like a hen needs a flag." を多用しているのはStephen Kingがほとんどで、今読んでる "The Running Man" の他に、少なくとも次の作品でも使っていました。
Stalking The Nightmare
The Mist
Haunted Heart
Skeleton Crew