I have had Silkies that were determined to roost with the Sizzles, who could fly pretty well. By jumping onto the nesting box and then the roost, he was able to get up to the roost about 40 inches high. With a ladder type of roost I later made he was right at the top. I finally decided to lower the entire thing. They don't fly well and getting down was dangerour for them. Moa actually got to where he would wait for me to come out and give him an elevator ride down on my arm. He was a character. I keep the roosting boards about 18 inches high in the Silkie coop and If they decide to roost they can. Most prefer to wad up in the corner. I don't mind that either, In winter I can insulate around the area they prefer and provide more warmth for them