Eli Lilly and Co. says it will file a plan in the coming weeks with the Securities and Exchange Commission for a potential initial public offering of a minority ownership stake in its Elanco Animal Health subsidiary as a separate company. Indianapolis-based Eli Lilly described the move as a prelude to shedding the unit and focusing more on its medicines for humans. It expects to complete the IPO process  before the end of the year. Noting that Elanco has more than six decades of experience in animal health, Jeffrey Simmons, the company president, said Elanco is prepared to become an independent company. “With a sole focus on animal health, we will help our customers address the greatest challenges of keeping animals healthy, and together advance a vision of food and companionship enriching life,” Simmons said.