Hi Frenchman Creek, The losses happened when they were fully exposed to a full blown blizzard. They were snow covered and the ones that died a few days later were wet and weak but hoped that moving them to the heated area would help them through but they were just too far gone by then. I even put one in the basement but it didn't revive. The others that were mentioned were lost when the cold first began and they were the youngest birds but still well over 10 weeks but they smothered under the other birds when they huddled for warmth instead of flying up on the roosts. That is when I decided to put the heat lamp back in but the other pen where the Opals and others were, were about a month older and I just didn't think to check after work as my hubby said they were fine but even he didn't think the magnitude of wind and blowing snow would cause such havoc. I thought the tarps were up but he had taken them for his calves and I didn't realize it. Now, I don't think I will divorce him over a few birds but he knew I was pretty darn upset.