Full-Day Kindergarten vs. Half-Day Kindergarten

My school is in the process of moving from a half-day kindergarten program to a full-day kindergarten program. With states requiring more and more from teachers and students, full-day kindergarten seems to be the best (and only) option. In terms of curriculum, I have plenty of ideas and my lesson plans are full. But I worry about the effect that my state's strict requirements will have on my young students. Can kindergarten students physically and mentally handle the demands of a full-day kindergarten program? Or are half-day programs more developmentally appropriate for our youngest students? Any suggestions for dealing with a full-day program in terms of scheduling, routines, and expectations are welcome.