Hello!!
My 5 week old girls lie outside now BUT inthe hen house with their heat lamp. Temps here are still dropping into the upper 40's at night. But yes, I do let them wander about when it is nice out. You will be able to tell if they are chilly or not...if they are wandering and looking comfortabe, then they are fine but if they are laying down and huddling..they are cold. I go with..if it feels too chilly for me, then it is too chily for them. I would not leave them out unattended though. I let mine out for a few hours in the afternoon when it is the warmest, unless we have one of those 75-80 degree days, then they are out a little more I have a fine wire over the front of their little door to their house so they can look out if I am not here to supervise them. That way they get some fresh air in there. It is about 65 here and windy and mine are out for a stroll right now.