If you are going to build your own roosts, don't buy the circular shaped wood. Use two by fours instead. It's a lot more comfortable and secure from my experience. Also, if possible, have two roosts instead of just one, even if you only have a handful of chickens. It will prevent fights over position on the roost from breaking out as often because there is more space to go around.
I've also attached a picture of the roost I built for my chickens. The ladder is for older chickens that need help getting up onto the roost because their flight capabilities aren't the best. I assembled the roosts mostly with screws and whatever these cool metal things are called. Also a rule of thumb is to make sure the roosts are higher off the ground then the nesting area is.
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