My setup is a 5'x5' broody pen inside a dirt floor coop. The pen has a people door with a 2x4 across the bottom, and the walls are a strong chicken wire, 6' tall. This morning I found mama and babies outside their pen, in the coop, along with #2 roo and 4 or 5 other hens. All was peaceful. I propped the pen door open. Evidently, the chicks had dug under the doorway 2x4, and mama had followed by going over the wall (I've watched other chickens do this; they half-fly, half-climb over.) Guess the chicks gave themselves a 2 week birthday present. Well, that was easy.