DENVER (AP) — A father whose four young sons could communicate only in grunts when authorities rescued them from a filthy Denver apartment has been sentenced to five years in prison.

Wayne Sperling was sentenced Tuesday after pleading guilty to his second offense of child abuse.

Judge Eric Elliff didn’t think the 67-year-old had learned his lesson and says he hopes this sentence sends a message that children can’t be treated like pets or possessions.

Authorities say Sperling, his wife and the boys lived in an apartment filled with cat feces and flies.

His wife was previously sentenced to 90 days in jail and five years of probation.

Prosecutors say the boys are improving while living together in foster care, but they still struggle.