In the version of "Soldier's Joy" heard, the fact that lyrics fit from "Chicken in the Bread Tray" is an example of what feature of folk music?

The feature highlighted in this example is the concept of tune families that can be interchanged in performance, which is fundamental to folk music traditions. In folk music, melodies often share common roots, allowing performers to adapt and borrow tunes in creative ways. The fact that lyrics from "Chicken in the Bread Tray" fit the melody of "Soldier's Joy" illustrates how musicians can take a pre-existing tune and overlay it with different lyrics without losing the essence of the original melody.

This interchangeability not only maintains the cultural significance of the tunes but also enriches the performance experience, as different lyrics can evoke various themes or stories while utilizing the familiar sound of the melody. Such practices are typical in folk music, where oral tradition promotes flexibility and variation in song construction, encouraging creativity and local adaptations throughout the community.