I also use 2'x4' with the large side horizontal, set in ladder fashion which leans at a 45 degree angle (no pooping on each other). Not that it's applicable much in our area but its better for their feet to be flat on their perch so they can cover them with their feathers in cold weather to prevent losing toes. At the least, it's more comfortable for them & I've always thought happy birds stay healthier & lay more. I've used big branches too (manzanita or oak, 2"-3" diam) because they look nicer but they take more finagling to get them cut so their mostly level & secured properly. Manzanita is a real pain because it's so hard - good for hookbills but not necessary for chickens.What is the best roosting material for the internal coop roosts. Ive been seeing lots of different roost designs. One guy had advice that large branches made the best roosts. Im thinking that whatever it is a rather significant diameter (or block surface) is preferable to some thing rather narrow.
I also painted my perches & coop floor with an epoxy paint. Super durable, won't flake, and I can easily scrape things clean.

