The white looks like new feather shafts to me, normal in a molt, but maybe I'm seeing it wrong. Some will have a light molt and just look a little scraggly, I have one girl who goes half bald and looks horrible! Depends on the bird.
Nope, not seeing it wrong those are new feathers coming in during the molt. I would also guess that some of the hens are pecking at and removing some of these new feathers from his neck. Very likely the healthiest most pristine looking hen in the bunch is a feather plucker/eater. Removing him from the flock until he completes the molt might help.