My research says that that's too little protein for good growth and too much calcium creating more possibility of renal failure. In addition to it can delay development and onset of lay. I think it's a bad choice.
To me people, who knowingly feed layer to chicks are just ignorant... even the long timers on here that we know and love!

It's fine for them... NEVER on my watch will it happen... (some people do what they NEED to also)
Layer is cheap because protein is pricey while oyster shell is cheap. If I want CHEAP eggs from chickens treated.. my version of crappy (via nutrient deficit in this instance), I can get those at the market. I keep chickens so my eggs and meat can be better in both flavor and nutrients in addition to the overall better life they get. You know the old saying you are what you eat... ya, I think so.. that's why higher protein is said to give better hatch rates (studies confirmed) because the eggs are filled with more nutrients!
I also always have broody's, chicks, roosters,molting, and juveniles. I feed 20% protein flock raiser with oyster shell on the side for layers to all birds start to finish. I don't consider it perfect, but it's what's available and works well.
The higher protein won't hurt the older birds and may even benefit them especially if they are dual purpose. It helps feathers grow in nicely since they are made form 90% protein and it's amino acids. I guess this statement right here is enough reason to not feed chicks a diminished protein diet to me.
Those who feed that way... their choice. Yes I guess I got a little judgey, because you asked specifically what was thought.

I wouldn't act that way to someone looking for help or be calling people out telling them they are ignorant. I would try to be a little gentler with suggestions since you attract more bees with honey than vinegar.

We all have choices and make them from our own perception. I just shared mine, so please try not to take it all harsh like and rude.
Best wishes making the right choice for your flock and self!