How big is your coop, in feet or meters? What do the rest of your facilities look like? How big is your run and do you consider it predator proof? How old are your existing chickens? How old are your new ones? Before I can answer specific questions suitable for your situation I need to know what you are working with.
In general, as long as mine are not sleeping in the nests and are somewhere predator safe I don't care where they sleep. Chicks sleep on the brooder floor, my broody hens take their chicks to sleep on the coop floor until they are ready to roost, my brooder-raised chicks sleep in a group on the coop floor until they are ready to roost, and some adults (like some Silkies that cannot fly) sleep on the floor. Sleeping somewhere other than the roost will not hurt them. They do it all of the time.
I'll stop typing and wait for your answers before I go further.