Why won't my chickens lay eggs in Minecraft?

My chickens are refusing to lay eggs! I feed them seeds regularly and they are in a medium sized pen so they have room to walk around. I read that they need sunlight so I ripped the roof off of their enclosure. Still waiting for eggs! Am I doing anything wrong? What should I do to make them lay eggs?

Which version, xbox or PC? Walk away for some time and come back.