I am glad to see the information sharing about general flock keeping as well as hatching here. Most of us read lots of things, and eventually discover conflicting information. When all else fails, your flock will tell you whether you need to change something.
As a general rule, as others have said, I do not feed layer. I feed a grower or all-flock/general poultry feed, and offer free choice grit and oyster shell, always available. I also give plain homemade yogurt, apples, meal worms, etc. as treats, and all my birds right now are getting a treat dish of scratch (DH calls it crack LOL) right before bedtime. I mix my own scratch. I mix cracked corn, whole wheat, rolled oats, wild bird seed, and whatever else is on sale or sounds good at the time I'm buying ingredients. Commercial scratch almost always has a ton of milo which my birds just don't eat that much of, and it is a waste. I hate waste.
When I am fermenting I mix all-flock/general poultry feed with my scratch mix. Here, for me, right now, FF doesn't work, but once spring is here I'll start fermenting again. I had to be out of town several weeks in a row 2-5 days at a time starting in October, and I do not expect DH to maintain FF, nor does he especially wish to, so I switched all to free choice dry plus treats. For several weeks I used Nutrena All-Flock and Starter/Grower, and my flock seemed to be on the decline, so I switched back to locally ground starter and grower and a Ranchway Poultry Feed for the adults, continuing treats and of course grit and oyster shell. When I read about the recall due to low calcium in Nutrena feeds, I upped yogurt, and figured I knew at least part of the problem.