I don’t feed a 100% layer feed, I do 2/3 layer and 1/3 Turkey/Gamebird due to having geese in my flock. If someone only has laying hens I would only use layer.Ca to P ratio is too high. As consequence, the hens can't use the calcium as effectively. Sadly, its even worse with some of the other feed brands. Sorry Nutrena.
I will respectfully disagree with GC and Rooster on this issue - I'm All Flock plus freechoice oyster shell for typical backyard owner, with typical backyard flock and typical backyard management - but readily acknowledge that the atudies show differences in egg size and frequency between typical 16% protein feed and 20% protein feed are quite small, too small for thw typical owner to notice. A couple eggs per quarter, and a gram or two in average egg weight.
and in the interest of full disclosure, i don't feed my own flock in the way i recommend for the typical, but i have neither a typical backyard flock nor typical backyard management, and feed according to my best opinion in balancing risk, cost, production (meat and eggs).
You are of course welcome to read the literature and make your own risk assessment in view of your own situation.