lagrange chicks
Crowing
I'm in Wisconsin also and did build roll away nest boxes. Last winter I may have had maybe 6 frozen eggs. I just checked for eggs a couple times a day when the temps are real cold since I need to give them water anyway (no heated water). I have a hen who likes eggs more then me I guess so the addition of a roll away box saves eggs all year long, loosing a few to freezing is fine and just thaw them and cook to feed back to them. This year everyone molted and haven't got an egg in over 2 weeks so no worry on freezing when there is none. 
