What are these lines on the nails/beans of my ducks’ beaks?

[mossp2002]

The ducks are all female and 3 1/2 years old.

They are fed Naturewise 16% flocksheild with a scoop of brewer’s yeast along with daily kitchen scraps.

Additionally, they free range on about an acre for a few hours a day.

 

[RossAcres]

It's genetic and normal. Increases with age. In show quality white call duck males, it is a disqualification. But other than that it's just an age thing. Nothing to worry about!

 

[mossp2002]

It's genetic and normal. Increases with age. In show quality white call duck males, it is a disqualification. But other than that it's just an age thing. Nothing to worry about!

This is relieving to know! Thank you