Duck bill issue?

[Hillwater farm]

Hey all, was wondering what you thought about this. Oval shape spot that appears worn? Noticed it a little on the other side as well. Seems perfectly happy otherwise, just can't find anything online that explains it and he's the only one that has it.

[/IMG][/IMG]

 

[Hillwater farm]

 

[Bills vs Beaks]

Could he of hit it on something rough or sharp? Ducks bills are relatively soft...
It's not bleeding right?

 

[Gray Farms]

Looks like he's chipped off a piece of his bill at one time and it hasn't fully grown back yet.