I have literally never seen one of my guinea fowl or chickens in a tree. We live in a forest with thousands of trees to choose from -small and large, hardwood, evergreen, deep in the forest, at the edge of forest, and out in mowed yards and fields. I had thought they would be in trees all the time, from what I read about them. But nope. Never. We built them a shelter that is 4x4 by 8’ tall with a peaked roof. It’s open on one side ... think a tall outhouse with no door. There are roosting bars at the top and up in the peak of the roof, and THAT is where they always sleep. We don’t make them - they are full-time free ranged. But they choose to be in that shelter.