It was about 65ish here in michigan today and I had as many of my chams as I could find trees to put them on out today in my back yard. In my back yard I have all the old trees from their enclosures planted randomly so they have mini free range tree spots. The trees are all 5ft-9ft high. I used a laser temp thermometer and their skin was in the mid to upper seventies when there wasnt wind. The sun was real warm today even with the cooler temps and all my guys brightened right up as soon as they got outside. My chams are miserable when they are inside, well not miserable but they def are brighter in the natural sun. The cage size for all my adults is between 6-8ft high and 3-4 ft wide and 3-4 ft deep so its not because of the space. I just think they prefer fresh air, real sun, and wild grasshoppers.