Bare backs and butts

[Vincentville farm]

I'm assuming this is from my rooster, but what should I do about it? And does it affect egg production?
I used to have one hen that showed signs of 'over riding' by my rooster. I despurred him and now I have multiple hens with bare backs and then some. The bare butts are the most confusing. His spurs are growing back but they are nothing like they were when I treated him. Is this more than just his aggressive desire to mate? I'm considering chicken saddles but don't know the specifics of their use: how often to change them, how long to leave on, what kind works, etc...
Any suggestions would be greatly appreciated!

 

[sourland]

I would expect 'rooster damage' to be further up on the back. Given the pecked butts in addition to the bare backs I think there is a bird/birds in the flock that are feather pecking/plucking.

 

[Vincentville farm]

I would expect 'rooster damage' to be further up on the back. Given the pecked butts in addition to the bare backs I think there is a bird/birds in the flock that are feather pecking/plucking.

If that's the case, how do I address it?