Chipping
The breaking of the eggshell prior to hatching. The first sign is the appearance of cracks radiating from the point of the first breakthrough ('starring'). The chick then enlarges the cracks with its egg tooth. An egg can be chipping for a period of a few hours or more than a day before the young bird is free of the shell.From Peter Weaver's Birdwatcher's Dictionary
Copyright © 1981 by Peter Weaver