How High Should the first one be? What distance should they be apart? How High should the top one be? How Many should you have for 12 to 15 Birds? What Thickness should they be? My First one is about 18 Inch off the ground and then there is about 12 to 15 Inchs between each one going up and about 10 to 12 inches width ways apart. The Dia of my RoostSticks is about 2 to 3 inchs. How high can Chickens fly?