My roosters (yes I know I shouldn't have 10) keep picking on the lowest on the pole. They have killed 3 birds in the last 3 months, 1 hen (crippled) and 2 boys. Should i establish another coop or roosting spot? My coop has good roosting places and nesting boxes but is very open. The boys like to attack each other just before bedtime. I was hoping the lack of snow and room outside to free range would change their pent up aggression. Any suggestions?