I have 11 four week old chicks. Yesterday we finished an outside area for them so they could come right out of the coop and into this fenced area. Last night we just opened the door and let them come out. It took about 30 minutes of standing at the door and the ramp for them to start out. We over the course of a few hours we got 8 to come out. The other 3 are scared to come out. Same thing today, those 3 won't come out. Is this normal?