I worried about the same thing at first. So I made a point to check each chicken's crop at night when they were on the roost. Amazingly enough, the crops were very full! They have access to all the layer pellets they want, but they don't eat much of it. They forage on grasses, tomatoes, apples, pears, table scraps, bugs, acorns, etc. They all know where the feed is if they want it. Some of the hens will pick at the feed at eat a bit before roosting. During the day, on occasion I will see a hen in the coop eating feed, but rarely. They are all large, fluffy, healthy looking birds, and laying well. I've decided to let well enough alone, and if a problem arises, we'll address it then.
BTW, mine get VERY upset if they aren't let out to forage. They were in lock down for two days (had to stay in the coop or run) because I wanted to make sure they knew where the nests were, and to see how many eggs I should be getting a day! They hated it! Even though I went out several times and threw some apples/pears/or table scraps to them, it just wasn't enough. They have lots of grasses/weeds/etc. still in their run, and they did eat lots of it. They also were scratching up the dried grasses looking for those bugs. They're favorite places to be are under the bushes, apple trees, etc. that has lots of mulch, and therefore, LOTS of bugs!! They'll also either take their beaks or just stomp on tall grasses to get the seed pods. They eat white clover leaves and blooms, oat leaves and the seeds, fescue, etc.
If they weren't getting enough to eat, or a balanced diet, I think their bodies would demand the layer pellets. Same was with the oyster shells offered free choice. If they need it, they'll eat it. If they don't, they leave it be. (Mine leave it!)