By the time classes start for about 10,500 Bulloch County Schools students Tuesday, their teachers will have been at work six days, including the first of four added countywide teacher training and cooperative planning days throughout the year. In fact, the 2017-18 school year includes just 176 class days, down from the traditional 180, under the calendar adopted by the Board of Education back in January. Under state waivers the school district can do that now, and converted the other days for planning or professional development, keeping teachers at their contractual 190 days.