Footage showed the boys falling asleep in their chairs, undoubtedly worn out by their ordeal in recent days.
The boys were abducted on the night of Dec. 11 from the all-boys Government Science Secondary School in Kankara village in Katsina state in northwestern Nigeria.
Nigeria's Boko Haram jihadist rebels claimed responsibility for the abduction. Leader Abubakar Shekau said they attacked the school because they believe Western education is un-Islamic.