I have 12 almost-2-week-old Cornish Crosses and 3 Barred Rocks. They're living inside in their brooder, and man, those boys are getting big FAST! They're also getting rowdy. When is it okay to let them go out on the lawn during the day to play? I'm sure they'd be fine with the daytime temps, but are they old enough to be nibbling on grass and bugs yet? Also, when is it okay to move them out to the henhouse? I will have a heat lamp out there, but it does get quite cool at night still (40s/50s).