The only reason I know of that is good for them to roost is if they are sleeping in poop. That's not good for their feet and they get their undersides dirty. If they are not sleeping in poop, then I don't know that it really matters.
I've seen people post on here that they want their chickens to roost so they are safe from predators. I lock mine in a predator-proof coop at night so I don't worry about that. I'm also not aware of any predator that cannot pick them off a roost.
My brooder raised chicks usually do not start to roost until they are about 10 to 12 weeks old, even with older chickens in there to show them where to roost. My broody raised chicks usually start to roost around 4 to 5 weeks old when Mama takes them up there. She does not take them straight to the roosts with the big chickens, but takes them to an intermediate high place, like the top of my nesting boxes, where they can still huddle together although they do not sleep under her.