Anita Rice, Salt Lake City, introduces her 20-month-old daughter, Chelsey, to television producer Michael Bloom, hoping Chelsey will get a part in an hourlong child development video to be made by Heinz Baby Foods. Bloom, president of Special Interest Productions, Provo, and his staff interviewed more than 100 screen hopefuls and their parents on Thursday at the Marriott Hotel in Salt Lake City. He will video-tape 20 children, from newborns to 2-year-olds, and send the tape to Heinz officials in Pittsburgh, Pa. Five children will be chosen for the video, which the company will offer as a premium.