We live in North Central Florida. It has been as low as 28 in the winter. Had the flock of 9 for a couple months, but we both lived around chickens when we were little kids. Built the coop with the North end and 1/3 of the West side wood fence and the rest chain link fence (apx. 12x14 total). Also have a tarp over a 1/3. Will my ladies need any extra heat when it's really cold? Thanks so much for any advice.