I tried putting them out last weekend - 11 were 6-week olds, 6 were 5-week olds. They were too cold at high 40's at night (60's day) and I brought them back in for another week. This weekend, 1 week later at 7 and 6 week olds, they're just happy as can be. A few nights of low 50's at night, 70's day, then it's going up to 80's days, mid/high 50's nights. I think that extra week made a big difference, plus gave me extra time to complete installation of galvanized wire under the sand floor to keep out the darned ground squirrels. Now a month or two of getting to be big girls, then the run door will open into their 20' x 50' space surrounded by 6' high hardware cloth, and covered with aviary netting.