3 week old mix breeds have outgrown their indoor box. Transitioned them outdoors today to their coop that is heated. Its reading ~75 in the coop. Its about 40 outside at the moment, but all the chicks were cuddled up and quiet. Anywho....I want to turn them out for a bit tomorrow, high is suppose to be about 55. Is that safe? And for how long? Or should I just leave them in their coop for another week before they are allowed out?