You’re reading comprehension is off. Nobody said switch 5 week old chick to layer feed.I can’t speak for others, but when I read the thread, it looked like people were replying to the OP’s comment about possibly switching to layer feed.
To the OP - yeah, what the others said, chicks scratch and spill feed everywhere! I have on occasion not filled their feeder right away (not for very long!) so they have to ‘forage’ for the kicked-out food. Gives them something to do and they scratch anyway.