Bruce
I have my roost about 2' up. I have an big English Orpington with toes about as long as my fingers. When she would jump off the higher roost, the thump was so hard I could feel the floor shake. She is one big girl and I was afraid she would hurt herself.
The fans do help a lot.
That tree is hawk protection. I lost my salmon faverolles to one a couple months ago and am now grateful for every single tree that I have. That was my first death and it was gruesome.