voice secured her voiceover roles, and she was cast to provide the voice of Lucy van Pelt in three Peanuts cartoons: the 1969 TV special It Was a Short Summer, Charlie Brown, a 1969 feature film A Boy Named Charlie Brown and the 1971 TV special Play It Again, Charlie Brown. She provided the voice of Sally, the little girl in the 1971 animated TV special of Dr. Seuss's The Cat in the Hat. Ferdin was a frequent guest star on episodic television in the 1960s and 1970s, with appearances on Bewitched, Green Acres, The Andy Griffith Show, Branded, Daniel Boone, Custer, The Monkees, The Flying Nun, The Second Hundred Years, Gunsmoke, Shazam!, The High Chaparral, Mannix, The Brady Bunch, Family Affair, Love, American Style, Marcus Welby, M.D., Sigmund and the Sea Monsters, Apple's Way, The Streets of San Francisco, Baretta, CHiPS, and 240-Robert. She had a brief and uncredited role in The Reluctant Astronaut (1967) and was featured in the Walt Disney musical The One and Only, Genuine, Original Family Band (1968). She appeared as Mary Constable in the supernatural TV movie Daughter of the Mind and as Abby Clarkson in the horror film The Mephisto Waltz (1971) with Alan Alda. The same year, Ferdin appeared in The Christine Jorgensen Story, based on the life of the first trans woman in the United States to undergo sex reassignment surgery, and in The Beguiled alongside Clint Eastwood and Geraldine Page. She then appeared in the Kurt Vonnegut adaptation Happy Birthday Wanda June, and in the exploitation horror film The Toolbox Murders (1978). She voiced Fern Arable, the little girl who raises Wilbur the pig, in the 1973 animated film Charlotte's Web. Ferdin was considered for the role of Regan MacNeil, the demon-possessed girl in the 1973 William Friedkin film The Exorcist, but casting directors decided she was too well-known and cast the less familiar actress Linda Blair. Her last acting roles were as the voice of the character Shelley Kelley in the Kids' WB series Detention in 1999 and as Christmas the Horse in the feature film Elf Sparkle Meets Christmas the Horse in 2008. In 2020, Ferdin co-hosted two episodes of the television talk show "Ken Boxer Live" on TVSB TV, originating in Santa Barbara, California. Activism After leaving her job as a public relations director in the mid-1990s, Ferdin began working for the Center for Animal Care and