I have 5 week old chicks that need to go outside. The thing is, it's in the 30s at night. Is that too cold for them? I brought them in last night because it got down in the upper 20s. They don't have much of a shelter, it's a doghouse with shavings in a fenced off part of the run, to protect them against the big chickens until they're big enough to fend for themselves. I really want them out of the house, they're defiling my sunroom.