Is that area soft and mushy, like it's raw and damaged tissue? I wasn't sure from looking at the photo. Looks like something took a chunk out of it. Is there something sharp he could have injured it on? Bite from a dog or something? Just throwing out ideas. Can you disinfect it and put antibiotic ointment or vetericyn on it. That's what I would do a few times a day - especially at night before bed when he won't be rinsing it off.
It's either what @CoriM mentioned or it's what I assume is a natural shedding of the very top layer. I noticed this on my drakes often but I don't remember if I've ever noticed my hens like this. My Pekin drake has this now and he's just finished his annual molt. I have always thought it was related. One of my Call drakes has this and he is beginning to molt. I don't ever do anything for it, but I know it's best to not pick at it, just in case it gets deep at any area. I'm outside now locking everyone up. If I can get pictures of my drakes that look similar, I'll share them here later tonight. Lockup usually takes me a while.
The best way to determine would be gently touching it. If it feels like Cori mentioned and looks raw, treat as she described. If it's flakey, I wouldn't mess with it. I'm mobile and it's difficult to see on my screen.
@WVduckchick@shawluvsbirds @BirdsBeesTrees
I know these ladies have had ducks, hens and drakes, for a while. I have a hard time believing this is a sex specific thing *IF* it's shedding
My apologies. Stormy was trying to eat what I thought was an acorn but he ended up spitting it out. After noticing some odd edges on this acorn, I picked it up and it was the teeniest of tiniest little turtle hatchling that I've ever seen! Thankfully it seems to be fine, but it's so tiny, like no bigger than a dime! So needless to say, I got a bit side tracked I did get a picture of my Cayuga and my Pekin. The pictures aren't great but you can kind of see the shedding. This is minimal for them as it's usually much thicker pieces. This is my Pekin drake, Reggie
And my Cayuga drake, Stormy (the turtle hatchling taster). I'll try to get pictures of my Calls bills tomorrow because I remember them having a bit of flakey/shedding bill too.