The Osmonds began writing and performing their own music and their sound moved towards rock music beginning with their album "Phase III". In addition to "Yo-Yo", "Phase III" produced the major hit "Down by the Lazy River" (#4). The following "Crazy Horses" album was the band's first really personal statement – the brothers have been quoted as saying that the title song refers to air pollution from cars, and its instrumentation featured an even harder rock sound bordering on early heavy metal. They wrote all the songs and played all the instruments with Alan on rhythm guitar, Wayne on lead guitar, Merrill on lead vocals and bass, Jay on drums and Donny on keyboards. All the brothers sang backing vocals, with Jay and Donny sometimes singing lead parts. But Donny singing co-lead on these songs was abandoned for the reason given below (except for "Lazy River", which he also did not sing co-lead on).