My chicks are 4 weeks old and have been outside during the day and once at night. We have had some great weather here in Maryland. Yesterday was high 70's. Today is mid 50's. They hate to be inside in their brooder box...too small for them. Do you think it is okay to put them in their closed coop - very roomy and nice. Hubby wants to put a heat lamp in there but it is going to be more than a notion and I expect another week it will not even be an issue. I don't want them to freeze but they are miserable in their brooder. Help!