The figurative use of the phrase was derived from the literal meaning of a young chicken, having tender meat. Restaurants of the past offered a young chicken, having tender meat, as spring chicken. Also, in observing a young spring chicken you are aware of its high level of energy as it runs around in a playful manner.
In the past middle-aged and older women often spoke of them self as: “I’m no spring chicken,” meaning they were no longer young, in good health and energetic.
Dub Mowery is a Gospel preacher in the Church of Christ. A native of Southeast Oklahoma, he is the author of Colloquial Sayings & Expressions (Morris Publishing, 2008)