I would like two roosting bars, one above the other. I am wondering what is the recommended heights they should be, but also how far away from the wall?
They should be far enough away from the wall that their tails don't touch when they perch...
...but aren't you worried about them popping all over each other? Maybe off-set the top perch to be closer to the wall than the one underneath? Like this:
They WANT to be high and will ALL try to get on the top roost whether it is 2' or 10' off the ground. If you can, make two parallel at the same height so those at the top of the pecking order (there is a reason it is called this) don't shove the lower ones down. They'll still shove them, to get to their preferred place of course, but those lower in the order can still roost high.
Assuming large fowl, not bantams:
Minimum 8" from the parallel wall so their tails won't be crowded against it.
18" between the roosts so they can't pick on each other. If they are stepped, not parallel, the 18" can be diagonal.
4' works well for my girls (though if it were higher, they'd be up there). If they get lazy, they use the 2' (put in for when they were young and couldn't make 4' directly) as a staging "platform". All of my girls can (and DO) get on the 3' high work bench with a hop and a couple of flaps. Not a lot of effort needed.
Hard to tell from this picture unless you enlarge it but there is a rear 3" round fence rail 12" from the back wall and a 2x4 on the flat 18" forward of that. The 2' high rail is 9" forward of the 2x4. The plastic pool steps were FREE. I put them in so the month old birds could get up 1 foot at a time. They have all slept at the 4' level from the time they were put in the coop at 4 weeks of age. I have:
- a group that sleeps on the front rail against the side wall
- a group that sleeps on the rear rail against the side wall
- a group that sleeps on the left end against the back wall - yes, on the 2x4 on edge that *I* thought was there only to support the long rails. The "spill over" from that board are on the rear rail. That was the "preferred" area for all when they were young. They spread out when they were older and it started to get cold.