Chicks went into the coop at 2 1/2 weeks. After 4 days I opened the pop hole door and left it open all day, closing it at sundown. It took my mixed band of banties 5 days before anyone was brave enough or curious enough to venture outside into their enclosed yard. I picked them up that evening to put them back inside. The next day, instead of picking them up and putting them in I brought a plate of "dinner yummies" and put it inside the coop and called for them...everyone came up the ramp and inside to eat.
Now I just have to call them and they will come in...looking for yummies before bedtime.
They don't like coming into a very dark coop so I have a red bulb on a timer that gives them just enough light to find their beds then turns off.
Using food to get them to go where you want them to go works wonderfully for chooks!