I'm currently raising Khaki Campbell ducks - they are 8 1/2 weeks old - and I'm wondering when the drakes with developing green heads. I read that they are fully feathered at 8 weeks, go through a molt at 4 months, which is when the drakes get drake feathers. Is this when they also develop green heads? I'm showing them in late July, so I want them to be fully matured. Also, I've pinpointed the sexes by voice sexing, as accurate as I may be, but I'm wondering if the males have the iridescent wing patches at this age, because the ones I presume to be males have them. Is that true?