The eye of the developing chick is very prominent after day five. The eyes are large and round. This is distinctive among birds. In some MRI views you will notice that eyes tend to have a well-defined boundary. Now, ask the question to your students.
Growth is steady, the volume increases by a constant amount every day.
Most of the growth occurs in the first week, and very little after that. Most of the growth occurs in the last week. Now comes the hard part - getting the facts. MRI is a way of seeing into the egg without breaking it. So a new set of pictures can be made every day on the chick.