The woodie (wood duck) hen probably had a cracked egg in her nest and yes maternal instinct they take it out. But they put the bottom of their bill through the hole and they just bite down on the egg and fly out with it and pretty much throw it away. Cracked eggs will ruin a whole clutch if it gets on any. Now the owl possibly hatching this woodie baby means that the woodie hen probably laid a egg or two in there and the owl pushed her out causing the woodie to have to nest elsewhere.I know. The wording is a bit clumsy and confusing, but you get the idea.