They should have roosted for some time already.A question? My 16 week old girls were sleeping in a nesting box .. we have since blocked them!!! They still won’t roost ! They just snuggle together in a corner of the coop! Will they ever roost! (
Now for the questions..
Your location and climate.
How many chickens do you have, and are they all 16 weeks old.
How high is your roost.
Is roost higher than nesting boxes, or same level.
Post a pix of your coops' interior, Much easier to give advice then.