I want to put out my chciks outside in the coop (seperate from the rest of the flock). Here in Southern Maine it has been in the high 30's to the low 40's at night. During the day it is in the 50's to low 60's. How warm do they need to be? Currently they are in my basement and under the heat lamp it is about 70F. The cool end of the brooder is 51F. Please let me know.