We have five young chickens between four and five months old: one plymoth rock, one buff rock, one partridge rock bantam, and two bantam silkies. Everyone knows to go into the coop on their own when it gets dark excpet for our oldest, the partridge rock bantam. She roosts on top of the coop and I have to coax her onto my hand and then I put her in the coop. If we put the light on inside the coop ( we run a extension cord with light bulb affixed temporarily ) then she goes in on her own. I have kept the light off the last week in hopes she will go in on her own, but no luck. Any suggestions would be most welcome!