Loss of feathers on the head is likely due to rooster mating.
On the chest, they are probably plucking out their own feathers, could be from rubbing on roosting bars. Skin is nice and smooth, doesn't look irritated, so probably doing it themselves, like a broody patch.
On the chest, they are probably plucking out their own feathers, could be from rubbing on roosting bars. Skin is nice and smooth, doesn't look irritated, so probably doing it themselves, like a broody patch.