My hens are 15 weeks old and doing great, they have been in the coop since 4 weeks and haven't a a heat lamp since. My question is at what temperature do i need to put a lamp in the coop, if at all. I don't want to wake up some morning to hensicles. There are 8 of them in a smallish coop, i use lots of pine shavings for floor. They do free range 2-6 hours a day right now.