(AP) — Two parents charged with keeping their four young boys in a filthy Denver apartment have both pleaded not guilty to felony child abuse charges.

Wayne Sperling and Lorinda Bailey arrived separately for their arraignment on Thursday in Denver. They stood before the judge, separated by their two lawyers, and they did not speak to each other during the hearing.

The case is not headed to trial anytime soon. Defense attorneys and prosecutors will discuss motions at a hearing on April 18.

The boys, ages 2 to 6, were removed from their parents’ home in October. Court documents say the children could communicate only in grunts, were malnourished and weren’t toilet trained.

A doctor told authorities one of the children reeked of cigarette smoke, prompting a welfare check.