This is my FIRST winter with the girls. I'm wondering if anyone has some tips for me. I have a garden coop with 4 hens (Golden Comet, Buff Orpington, Barred Rock, and Easter Egger) This coming week will be the coldest for the longest they have ever had to deal with. I have no heating for them and I want to know at what point do I have to really worry. The run has plastic up and there is plenty of ventilation. Theres straw of the run floor and pine shavings in the coop with some straw in the egg box. PLEASE GIVE ME TIPS! I would hate to loose one of my girls.