I like your theory! It fits with when I see my drakes bill look the worst. Which is in winter after he has molted into his breeding plumage so his hormones should be high.I'm the weirdo who has been thinking about this all night so this morning I went out and checked my drake's and hens bills. The drake's definitely have it more noticeably and my hens that do have the shedding it's fairly minimal and more right around the edge of their nares. I've been searching for studies all morning and have yet to find any specifically on duck bills. The only thing I found was the usual duck bills are made of keratin and it stops right there. I'm curious if it is similar to facial hair. Most males grow noticable facial hair and most females have barely noticeable peach fuzz. Since ducks don't have keratin in the form of hair, but bills, feathers, etc. I'm wondering if the testosterone in the drake's is triggering a surplus of keratin turnover. Hmmm now I want someone to do a study on it because this is going to bother me probably forever
Feathers are made of keratin too, right? Because my drake seems to molt more often and more feathers than my girls. It would seem like if hormones were turned on to increase feather growth it would also increase bill keratin growth?!
This is my pretty boy’s bill now:
