Last year, Alabama enacted S.B. 262 (e-mail me at firstname.lastname@example.org if you would like the full text of this measure), which calls for the School Superintendents of Alabama (state-level professional organization) to develop and administer a professional development program for all superintendents in the state. The program must draw from the National Staff Development Council definition of "professional development", and contain specified elements supported by research and best practice. The legislation also requires all new superintendents to participate in the School Superintendents of Alabama's Mentor and Executive Coaching Program, to train participants in specific skills key to the superintendent's job. Per the legislation, every new superintendent must be assigned an executive coach (an experienced superintendent), to make at least 8 contacts a year and hold quarterly meetings with the mentee to work on several key issues, i.e., "Budget development, instructional planning and personnel actions, School system actions that must occur in the upcoming three-month period, [and] Identifying and addressing the issues and challenges of running the school district." A new superintendent can opt into a second year of mentorship.
In addition, a 2009 administrative rule adoption (e-mail me if you'd like the full text) rewrote the state's provisions on leadership development, making numerous changes (not necessarily related to the legislation).
Relatively few states appear to have statewide policies on professional development for new and experienced superintendents, much less requiring professional development for district leaders to be based on research and best practice.