I second this-I actually don't worry about them roosting at all, because mine get locked up in a pen during the night, so it doesn't matter to me whether they decide to roost or sleep on the ground.
As long as you feed them the same food for the rest of their life and keep them in a pen, knowing what to eat and not eat doesn't matter. Some adult chickens still don't know what they shouldn't eat, hence why you see random ones eating even things as strange as glass.
Fun fact: chicks are hatched with the ability to know an object still exists even when it is taken away and put where they cannot see it. This is an ability that human babies and toddlers do not have.
Chicks are hatched with most of their instincts. They know how to roost, scratch, peck, drink, eat, fly, etc. You don't have to teach them any of that, and you can't, given the fact you are a human and not a dam. One thing you do have to do is to dip their beak in food and water when you first...