Looks to me like your rooster is an active boy!
The balding is typical on the top of head, neck and back when a rooster is constantly trying to mate your hens.
If you don't care if your eggs are fertalized, separate the roo for a while and let the hens feathers grow back.
the RIR with the spots on the chest looks like possible moulting?.....how many birds do you have in what sized space?
If you think its them all picking on eachother then I would allow them more free ranging room.
e