The superintendent receiving a person committed to any of the institutions shall ask the person to state the person's religious preference, shall enter the stated preference in a book kept for that purpose, and shall request that the person sign the entry. If the person is a minor and has formed no choice, the preference may be expressed at any later time by the person.
Iowa Code § 904.510
83 Acts, ch 96, §26, 159 85 Acts, ch 21, §54