Localised beak infection?

[fredwck]

The beak is crusty near the top and since today one bit broke. I suspect infection rather than physical but otherwise he is eating drinking playing well. Is it contagious? Topical antibiotics/antifungal? Others in the same house seems unaffected.

 

[Isaac 0]

Personally, it appears to me as if he injured the area.
The flaking, and dryness going on is not uncommon and can simply be the result of a dry environment. An antibacterial ointment over the injured part may be good for a couple of days, but it should resolve on its own completely fine without intervention.
Duck bills go through a lot of beating consider how they use them so don't be surprised to see scrapes/bumps/flakes etc.