My 10 or 12 week old Brahmas and BO have never been on a roost. Last week I added approximately 12' to the length of the run they are in. And i put a roost bar 12" off the ground in one end. Six or seven days and at night they still squat in a corner in the chips. They seem to be exstatic over the addition, but how old are they usually, when they start to roost. My Wyandottes and Speckled Sussex started roosting the day after I gave them a place to roost, at approximately two or three weeks.