I have all options in my coop.
2x2
2x4 flat side up
8 inch wide shelf
2 foot deep table
Chickens use all and do fine. They fight over the shelf since it is the highest. They do prefer the wider roosts.
2x2
2x4 flat side up
8 inch wide shelf
2 foot deep table
Chickens use all and do fine. They fight over the shelf since it is the highest. They do prefer the wider roosts.