The term "hay-foot, straw-foot" originated during the Civil War as a reference to inexperienced soldiers, or rookies. These new recruits were often so unfamiliar with military drills that they struggled to understand basic commands, like distinguishing their left foot from their right. In response to this challenge, drill sergeants devised a method to help them keep time during marches by tying hay to one foot and straw to the other. This creative solution allowed the new soldiers to learn the rhythm of marching while still highlighting their inexperience.

As the chant "Hay-foot, straw-foot" echoed during drills, it became synonymous with these naïve recruits, particularly those who struggled with basic tasks. The phrase reflected the frustration of seasoned soldiers and drill sergeants alike, who faced the daunting task of training these greenhorns. While it was a playful means to address their lack of military knowledge, it also underscored the significant challenges faced by the Union army in cultivating effective regiments from a population of largely untrained volunteers.