When I add new chickens, I always go out at dark and check where everyone is. If I find one not on the poop board roost....I take it from where it isn't suppose to be and put it where I want it. After a couple times of moving them.....they are where they belong!
That's the way to do it! In the afternoon sun, all of mine usually come back in the coop and prefer to lay in the pine bedding on the floor - I presume to stay cool. But at night, they're all on the roosts now!