Mine never have....mainly they have lost the roo tail feather or two, some feathers at the base of their tail and a scattering on the neck....but never very much at all.
I've never seen mine lose them at all....so I guess they just didn't molt and regrow those particular feathers when I would have noticed. Maybe it happens a few at time? Not sure.
Depends on a lot of factors. Some being: Climate or temperature, Breed of chicken, Individual chicken, Diet. Mostly in my are (MS) it all depends on the rooster. Some molt a lot heavier than others. High protein diet, particularly in the hot summers.
Yes roosters molt all feathers. Some birds drop almost all of their feathers in a full blown naked-making type of molt while others just replace feathers a few at a time.