The key nutrition numbers to watch are calcium and protein.I only have 2 chickens. I had 3 and something got one. I plan to get more once new hen house is set up. I’m in Arkasas. I’d really like to know about layer pellets. Lady I got them from suggested these. I will lay off scratch. Thank you!
Layer feed will have about 4-5% calcium, to help laying hens make strong eggshells without depleting their bodies of calcium. Chickens who are not laying - including elderly birds, roosters, pullets, cockerels, and chicks - don't metabolize the excess calcium very well. In fact, it can cause damage to livers and kidneys.
There is feed designed for the whole flock, some names are All-Flock or Flockraiser etc, which contains about 1-1.5% calcium. It's fine for all ages and sexes. You should put out a dish of crushed oyster shell on the side. Laying hens will take the extra calcium they need from this, and other members of the flock will leave it alone. The birds know what they need.
Layer feed and All-Flock types will have about 18-20% protein. Some feeds have more or less, depending on the species and age of other birds or chickens. Folks who grow certain broiler-type and fast-growing meat breeds will opt for 28-30% protein (commonly found in some game-bird feeds).
Chick starter feed can be fed to all ages, too - as long as you supplement the calcium with oyster shell on the side. It's very similar to All-Flock.
(My birds are currently getting a gamebird grower/finisher feed with 22% protein and 1.3% calcium, with oyster shell on the side. I opted for a higher protein to help the birds get through molt, grow new feathers, and provide extra energy for the cold winter months. Plus it will help with egg production, should they choose to lay. Also, about half my flock are still growing and I figure the extra protein would be beneficial. Once they all reach maturity and weather starts to warm up, I'll switch them back to All-Flock. Finally, I have a tub of medicated chick starter feed that's used solely for my chicks up to about 6-8 weeks of age. I hatch my own and they are not vaccinated, plus there is the ever-present risk of coccidiosis - so the medicated feed is warranted.)
Now then... about scratch grains. They are beneficial for the birds and gives them an extra boost of energy. However, due to the low protein content (about 7%) and lack of other vitamins and added minerals, it should not consist of more than about 10% of their diet. Think of it as dessert for your flock, or candy - but not the basis of their diet.
I hope this helps!