when you say that we should be able to let them free range all day in Central Kentucky do you think the hawks aren't an issue?
I was talking about them being able to leave the coop and go into the run, not free range. Sometimes they can be stuck in the coop.
For some people hawks are a huge issue. For some, not really. For some it's only during migrating season. I don't know why. Variety of hawk or the size of your chickens might play into it. Maybe how much food is available, whether that is rats, rabbits, or other birds. Terrain or how much activity you have. Hawks can be a problem.
I may be confused about a pullet vs hen - we have 7 laying girls right now and 5 girls who are still pullets (the 4.5 month old ones, the laying hens are 6.5 months old but maybe they are still called pullets because of their age?).
I saw where your cockerels are 4.5 months old and made the mistake thinking you girls were all the same age. I should know better than to assume.
Technically they are pullets and cockerels until they are a year old but that's not how I was using the terms. I was thinking about behaviors. There can be a big difference in behaviors between immature chickens and mature ones. My pullets tend to act like mature hens about the time they start to lay, whether that is at five months old or nine. Cockerels are harder. I've had a cockerel act pretty mature at 5 months, I've had them wait until 11 months. Most do OK around 7 months but it can really vary. The girls' behaviors can have an affect on that too. Some are more ready to accept a cockerel than others.
When the boys are immature hormones can take control. The boys have little to no self control and can get pretty wild either fighting each other or going after the girls to mate them or just dominate them. Immature girls don't know what is going on with the boys. They may fight back but usually try to run away. That doesn't calm the boys down any though I'm not sure much will. When they all become mature things tend to calm down a lot, but as someone on here once said watching cockerels and pullets go through puberty is often not for the faint of heart.
With your older pullets they may smack that cockerel around if he gets too feisty, but if you are getting fertile eggs they are pretty much accepting him. That is a good sign.
Is this something you think we can try to work through with a second coop and the pinless peepers for now?
You can certainly try. If you ever see blood try to isolate him pretty quickly, it can go downhill really rapidly.
Are you kidding?

Chickens aren't going to do your mental bidding! You will need to teach them by repetively placing each on his own side. After a while perhaps it will become a habit. The odds are in your favor after spending days of repetition. Nothing is easy where chicken behavior is concerned.
That's funny but it has a lot of truth in it. Repetition can break habits or teach new ones.