In February 1967, Country Joe and the Fish entered Sierra Sound Laboratories to record their debut album, "Electric Music for the Mind and Body", with Charters and Denson overseeing the process. Prior to their studio work, Armstrong left the group and began a two-year alternative assignment as a conscientious objector, driving a truck for Goodwill Industries. Francis-Gunning was involved in the beginnings of the album's development but left when the rest of the band complained about his drumming technique. He was replaced by Gary "Chicken" Hirsh. The next recording session was postponed for three days as the most recognizable lineup of Country Joe and the Fish rehearsed with their new drummer at the Barn, in Santa Cruz. Hirsh's abilities were immediately distinguishable on the album, as he demonstrated an acute and articulate drum beat that music critic Bruce Eder praised as "some of the best drumming on a psychedelic record this side of the late Spencer Dryden".