The chickens are stressed, possibly nutritionally. Feather damage does not appear related to rooster conflict as it can occur in with hen-only groups as well. The feather-pecking and egg-eating behaviors might be slowed in part by upping dietary protein level. I would even introduce some hay, making sure you have sufficient grit available beforehand. Slow introduction better so they do not over consume. The ability to glean hay seems to distract my birds from feather pecking. The parasite issue needs to be followed up on.
A piece of plywood can block roosters trying to fight through a partition.
A piece of plywood can block roosters trying to fight through a partition.