Ducks with partially black bill, help please!

[sqweek01]

My two 'aylesbury' ducks have got a partially black bill. It starts at the top near the nostrils & extends to about half way down.

Does anyone know what it could be? Or point me in the direction of where I could find out?

Thanks in advance

Clare

[BigJim]

Assuming there are no bumps or blistering, this may just be a bit of pigmentation. My ducks bills tend to go darker with spotting over time, although the drakes seem to stay unblemished. It also seems to start at the nostrils as you mentioned.

From Metzer Farms Frequently Asked Questions | Ducks and Geese

What causes the black spots on my duck's bill?
Black spots on the bill and legs are due to melanin skin pigment. They are normally present (not harmful) but are covered with yellow colored xanthophyll pigment absorbed from feeds containing corn, alfalfa and other feed ingredients containing xanthophyll. In mature breeder ducks, after they have been laying eggs for awhile, more xanthophyll is absorbed by the egg yolk than the duck can consume in her feed. The bill and legs start showing melanin skin pigment due to the bleaching or fading of the xanthophylls.

[squibbs]

I was going to say they were probably chewing on their biros whilst working out their bill.

...I'll get me coat