Section 65. Courts shall designate suitable times for the hearing of cases of children under 18 years of age, which shall be called the juvenile session, for which a separate docket and record shall be kept. Said session shall be separate from that for the trial of criminal cases, shall not, except as otherwise expressly provided, be held in conjunction with other business of the court, and shall be held in rooms not used for criminal trials; and in places where no separate juvenile courtroom is provided, hearings, so far as possible, shall be held in chambers. The court shall exclude the general public from juvenile sessions admitting only such persons as may have a direct interest in the case, except in cases where the commonwealth has proceeded by indictment. A complaint under section sixty-three may be heard in such juvenile session.