I have a brick coop with a roosting bars on one end that cascade down and has 4 bars on it. Some of the chickens are opting to use nesting boxes rather than the bars. The coop has 10 guinea keets about 2.5 months old, 5 pullets, and a roo. There is plenty of room to add roosting bars but not really sure if I need to change the design or just add more to get everyone on it at night.