They eat to meet their energy need.. it's up to you to make sure it's balanced and appropriate. It varies by season, temperature, laying output, day length etc.. they will self regulate energy and calcium content when possible but not other nutrients.
Quality is subjective and so is "more protein".
Use a formulated, age appropriate ration and don't feed too many excess high energy, low nutrient treats like cracked corn, scratch, etc. (>10% of total daily CALORIC intake.)
They do not need access 24/7 as they don't eat in the
dark but rats do. So having as much as they want from sun up to sun down is ideal. Do you have lights on inside your coop where the birds are up and about at night? Some folks who deal with freeloading song birds and the like may do timed and measured feedings.. everyone has a reason they do what they do. I collect feed or close lids nightly and open or return them every morning.
Each hen will have a different amount of abdominal fat that correlates some to their breed and body type.
If no one told you.. or you don't already know.. at the stated age they are likely to molt this fall/winter.. That is quit laying eggs, lose their feathers, and put all their energy to regrow new ones. They will usually return back to laying as daylight increases back in spring.. Laying hormone is light driven. If you desire a return to laying sooner then adding in artificial lighting after they complete their molt is an option (research the method if desired).. noting they are hatched with all the ovum they ever will lay already on board, so this natural break just means they may possibly lay longer into their lifespan. But that only counts of course if nothing else happens.. predation, illness, injury, etc.. sorry for sharing my overthinking in the previous sentence.. it get's debilitating at times knowing whatever I say there is almost always a counterpoint.
Using a "flock raiser" (20% protein) with oyster shell on the side.. can help tremendously.. during this time (molt).. as feathers are made from 90% protein and it's amino acids.. gals not in lay won't need the excess calcium of "layer" and those who do need it will access the side. I made the switch full time after learning about protein content as was surprised at the difference it made compared to using "layer". Protein and calcium content is the main difference between most of those rations.
Do you happen to know what breeds your new ladies are? How many of them did you get? Are you getting eggs already?
Pics welcome and congratulations, I hope you enjoy your new chicken adventure! tban ks