My chicks are 6/7 weeks now,pretty much feathered, theres 4 of them and the coop/run is done and ready, the last couple of days i'v been putting them out all day till dark then going and gathering them and bringing them in to there nice warm cage and heat lamp. but i dont want to do this anymore. so my question is, it is now getting down to the 40's at night here. can they handle that if i leave them in there coop (4'x5'), i want them to start getting adjusted to the cold cause within the next month it will be much colder here. or should i run a heat lamp out there? and if i need to, should i only turn it on a couple times a night or should i leave it on from dark till dusk? i know that i will have to use the lamp during the dead of winter for there first winter most likely. but i want them to adjust as easy and soon as they possibly can!!!!