I have a flock of 13 week old BCMs who are kept in a coop that is an extension of the barn and looks like a garage with an open front. The coop wall is set back about 6 ft into the barn. I have another flock of mixed hens and 1 roo who free range. 3 days ago I opened to door to the youngsters coop and they won't go past the invisible line they have drawn right at the barn entrance. The other chickens range all over the place so I don't think they are intimidated by them or the roo. He basically ignores them. There are 7 cockerals in this group of 21. I thought after a day or two they would begin to venture outside. We even put tomatoes and watermelons out to lure them but no dice. They'll only eat whats on their Invisible line. What's up with these chicken chicks?