Hello to all, I'm new so please bear with me. This is the first year we are hatching. We started hatching guinea eggs in April from our guineas. We bought chicks this spring, and a few pullets. When the pullets started laying 2 Buff Orpingtons went broody right away. Of, course in the yard-flower garden. when we moved the nest to the coop they stopped sitting. So now we have chicks 2 weeks old in east central Iowa and frost this morning. How old do the chicks have to be before we could consider starting to get them outside?