THis is a toss up.Depends on the number of eggs and size of eggs the hen is bred to lay.
Egg laying requires huge amounts of protein and calcium and other nutrients. THe standard 15-16% protein in a complete feed is low but the laying hens eat a huge amount of this feed when laying. I have one easter egger who provides us with 1 xlg egg a day. Basically a lot of nutrients go into making lots of eggs a week and of course larger eggs require a high level of nutrition. I'm trying to say it's all relative. SOme breeds give 2 eggs a week; other breeds up to 7. Some give peewees, some XLG. That's a big difference in nutrition.
All summer my girls, once laying, were grabbing every earthworm possible. THis was on top of grasses, commercial layer pellets, whole corn and oats, food scraps, grasshoppers, bugs, meat scraps. THey ate animal protein, greens, and grains. Commercial layer at 15% protein and 3% calcium, kept the egg count high.
In my region the weather is getting cooler, preparing for a cold and snowy winter. THe bugs are disappearing, worms are ignored, grass is well cropped (pun intended) and egg count is slowing (it's fall). THeir appetite decreases as the egg counts decrease. Now I'll give more gamebird at 20% protein at 1% calcium and put out calcium supplement like eggshells. Because their appetite is lower and the bugs are disaprearing, I like them having the higher protein% in the feed. THey can use the protein for eggs or to rebuild their body. Calcium is needed to replenish the calcium stores in their bones or make egg shells.
Animal protein requires a lesser amount to meet nutritional needs; plant proteins require more and more careful formulation to meet the individual amino acid requirement. Corn and soy; beans and rice. THese combos have the correct complementary aa for plant proteins. A little meat is very beneficial. ie insects, worms, moths, beef, fish,etc.
In general, the theory of commercial feeds is to provide all the nutrients needed for good production and generally good health using the cheapest feed stuff possible combined with a vit/min supplement and calcium. IMO, these feeds lack fresh vegetative matter and a meat source. These are chickens, not vegetarians. IMO 15% protein is too low without a meat source.
Hope I made sense. Good thread.