I have nine bbs Orpingtons, three black and six blue, including a black rooster and a blue rooster. One of the blue hens is deeply attached to the black rooster, and those two dominate the other seven. They are kept in two coops (see My BYC Page), the blacks and the rooster's blue girlfriend in the west coop, and the other five blue ones in the south coop. Last night they ALL gathered and roosted together in the west coop; it was very windy and about 10* F. They seemed to know that they could keep that four X eight coop warm. Each chicken is the equivalent of a ten-watt bulb, so they had what would have been a 90-watt bulb burning all night. At 9:30 A.M. this morning they were all still up on the roost, close together, and perfectly comfortable. I, on the other hand, was freezing while checking on them. They told me to close the door and go back in the house.