I brought mine out at a week and a half for short times on nice days (I live in Maine) and they have done beautifully. I figure the mama hen would have them outside. Just make sure they go in to the brooder to get warm after a little while. 70 degrees is much different than 85 or 90. MIne are three weeks old this weekend and they're now outside three times a day for up to an hour. They come in and fall fast asleep, I think it keeps them from being bored too! They're starting to be a challenge to catch though. Its funny, if I stay stil they climb all over me but if I go after them to put them back inside, instinct kicks in and they're off like a flash! The easiest one to catch is always the last one, because she realizes she's all alone and just stands and peeps.