In my experience with chicks It is best to open the brooder and let them venture out at there own pace. We crawl before we walk so to speak. A small encouragement never hurts but In most cases If one goes they all follow. start them early and be careful they will get comftorble laying outside bathing in dirt digging cooling holes, and falling to sleep.
so build some walls to there brooder entrance depending on your set up. and slowly shoo them in remember we never want to stress our chicks. so do this gently. repetitive every night when the sun starts to set.
Soon you will notice your chicks coming out and having a happy day in the sun and returning at sundown. (chickens can't see in the dark so they always return to saftey provided you remind them daily while there young where that saftey is.
