Should the roo be separated?

Sounds like the old hens need a break form the roster. I'd boot the 4 bareback hens to a different pen and leave the roster and the 3 other hens together.

 

You are going to have to separate the bareback hens from the rooster one way or another if you want their feathers to grow back. Which ever way you do it won't create any problems.

 

Since you say the oldest hens are missing feathers, is it possible that these older hens are just molting? It is the most common time of year for molting.

 

I would leave them alone together, especially if he is a good rooster. The hens will molt anytime now and grow in their new feathers. He will probably calm down now too since he is a little older. You could probably use 3-5 more hens for him, but I would just raise some chicks in the spring. Too many people on here keep getting sick chickens from other people who in turn, make their other chickens sick. I made my bareback girls little sweat shirts out of polarfleece one year. They were just in the shape of a hen apron, but had slits for the wings, which held them on.

 

Yes, it does sound like the rooster is causing the bare spots on the backs of your older hens. The rooster grabs the feathers on the back with his beak. You might separate the rooster from the hens for a while, or they sell hen saddles that are cloth and tie around a hen to protect the hen's back.

A hen can go through molt and still lay eggs, but the laying rate will at least greatly decrease.

There are soft molts and hard molts. A soft molt is where a hen loses feathers over time but you might not even notice it is molting. A hard molt is where the hen loses most or all of its feathers at one time.

I am not sure what you mean by hens' bottom feathers looking like a little pouch. I am guessing just because they are older hens.

 

Compare your own now vs. 20 years ago when you were a young pullet and you'll get the idea.
Hope this helps.