The parents, who lived in Perris, have pleaded not guilty to more than 40 charges, including torture, false imprisonment, abuse of a dependent adult and child abuse.
The Turpins have denied all charges. The Riverside County district attorney reportedly said that if the case goes to trial, the children are prepared to testify, according to CBS.
David and Louise Turpin entered pleas Friday to three new charges of abuse.
The next court date in the case is March 23, to go over the status of proceedings. David Turpin's hair appeared to be trimmed and neater around the collar. "They talk about how warm and loving these kids are and so appreciative", she said.
The case drew global media attention and shocked neighbors who said they rarely saw the couple's 13 children, who range in age from 2 to 29. Prosecutors have said the siblings were starved and beaten, and that the Turpins would sometimes punish their children by chaining them up for weeks or months at a time.
David and Louse Turpin are scheduled to appear in a courtroom in Riverside for a conference about their case.
Authorities said the children were starved so severely that their growth had been stunted, and they were only allowed to shower once per year. She had just dropped her own child off at a nearby high school and was headed home when she saw the attempted abduction, Santa Ana police Cpl.
Mr Turpin is also charged with forcefully performing a lewd act on a child under the age of 14.
"That's a big deal, deciding what they're going to read, deciding what they're going to wear, these are all things that are decisions they make every day that are new and empowering", said Osborn. "Sometimes in this business we are faced with human depravity".
Some of the 13 siblings allegedly held captive by their parents in their California home are "starting to make plans for their future", Corona Mayor Karen Spiegel told ABC News on Friday.
"I think that this case really hit all of us deeply in our heart, and we want to do anything we can to help the children", Marta Cortez, owner of Eduardo's Mexican Restaurant in Corona, told the television station. They had previously resided in Fort Worth, Texas.
According to sheriff's investigators, the family moved to Murrieta in 2010, then to Perris in 2014.
The case drew global media attention and shocked neighbours who said they rarely saw the children, who appeared to be skinny, pale and reserved.
Instead of becoming famous, the Turpins have become infamous.
Caleb Mason, an attorney for the older Turpin siblings, said Friday that "our clients are doing very well in their recovery".