Well first kids don't have time in the morning to eat breakfast and get all of their thoughts together. Most importantly kids are thinking about sleep and not there school work and teachers yelll at them and there not learning there taking in the bad things and not having positive feed back by the ones they trust
Students will focus more because they will have more time to rest the brain. Less stress is caused because students will have more planning time in the morning. And studies show that a students performance is better at a later time in day.