I tacked a 2x4 at a roughly 45 degree angle in one corner about 18 inches off the ground. They used that for ages until they saw the nest boxes, now they roost up there. I ended up making a roost over the nest boxes and a poop board.
I think its healthier for them. they poop lots and lots at night and its better if they are able to drop it below them rather than sitting in it while they sleep.
Chickens always want a roost weather a day old or a month.. Depends how many chicks and how big the brooder is and how old they are as far as what they should be for roosts.. We have 18 chicks in a coop and we just went to a fallen tree and cut off a branch thats sturdy and long and had 2 nice branches to support it as a base... I saw one person use 2 red solo cups with a pencil between them for day old chicks.. They arent picky, they just want a roost