Roosts - you don't want to build them one on top of the other.
Well.. See for yourself.
As you can see here, only the top dog (or chicken in this case), will be happy and healthy. This pecking order is not one you or your chickens want to live with...
SO... instead we recommend, that if you have roosts that are at different elevations, you stagger them - or stair-step them up - so that no roost is directly above another one (it should look like a ladder leaning against a building). A recommended spacing between each roost is at least 12 inches, if not 18 inches.
Another option (beside the stair-step design), is to put all the roosts parallel, or on the same level. This can also cause less pecking order problems between your chicks. If you only have 2 chickens this would be pretty easy... even in a small coop you could just have 1 bar for both chooks to roost on. On the other hand, if you have several chickens, you might also need several roost poles. Or at least 1 long roost that they can all fit onto.
Also bear in mind that the higher your roosts are the more room you need to allow for your chickens to gently swoop down.
I hope you enjoyed this quick little chicken coop tip.