Perches for Chickens
Perches can be used providing they are of suitable size. Ideally two inches square, slightly rounded and removable to prevent young birds roosting too early (which can cause crooked breastbones). They should be positioned at an appropriate height to allow birds to get onto them easily, but high enough to prevent roosting on their nest box.
A dropping board under the perches which can be removed easily for cleaning will help keep the floor of the pens cleaner. Hens do two thirds of their droppings at night. You can also check the droppings for colour and consistency (as a guide to health) more easily.
Check birds regulary after they have perched for lice and mite, at the same time keeping a close eye out for scaly leg and any signs of respiratory noises.
If you marked the spot where a chicken slept, you likely find that chicken in the exact same spot the next night.