Big bump in her pouch on her "chin" - directly under her mouth. The bump will shrink a bit after a couple of days and then grow. She will stop eating and keep her mouth closed for the most part. You can sometimes see eggs in her mouth (if not fully closed) if you look closely.
On some peacocks and haps, you can actually see through her pouch to see orange eggs and later eyeballs.
EDIT: Most of the time, though the female isn't actually eating, she will dart at food and appear to be doing so. Watch closely.