here's a much more scientific explanation.I agree, and thanks again for the info it has been helpful.
I'm glad I said something about them or I might not have known. (that's why I like BYC)
I'm glad you said something too. Perhaps someone is interested in an all drake flock and would be interested in your boys. And you can always eat them. How certain are you they are boys? I can always hope they are girls!
http://www.metzerfarms.com/Articles/CrestedDucksUnusualBrains.pdf