I have 8 week old chics dying to get out of the brooder box. They are constantly trying to fly out . Our nights get to about 40 here . I have about 20 older birds in the coop that free range of the day . I dont have electricity in the coop nor can i afford to run wiring. Will they be safe if maybe i build a fence in the coop w leftover chicken wire ? And will it be too cold . The floor is plenty deep with pine shaving . Birds are good sized and fully feathered . THank YOu for all ya'lls help!!