| At what point do parents throw up their hands and send their children to Christian schools instead? |
Images from local TV station TVC taken after the captives were released showed a group of mostly young men and teenage boys. Many were emaciated. An infant was also among the group.
"We eat one meal a day," freed captive Olalekan Ayoola, told TVC, saying the food was not fit for a dog to eat.
Nigeria launched a crackdown on informal Islamic schools and rehabilitation centres in late September after a man was refused permission to see his nephews at one institution and complained to police.
Many captives have said they were physically and sexually abused and chained up to prevent them from escaping.
Other sites raided in major police operations have been in the mostly Moslem north of the country. Ibadan is in the southwestern state of Oyo, which is predominantly Christian.