Last night it was forcasted to go to -12 degrees F and the winds were blowing sustained at 15-20 mph. Since I have a diverse variety of birds, peafowl, turkeys, ducks, geese, chickens both large comb and small and a silkie and showgirls, I was concerned about some of them being able to handle the temps.. All but the ducks and geese [their insulating isn't finished as of yet] are in insulated, full sized buildings. The peas and turkeys are housed in a 16'x12' building with seperate pens. The peas were the ones I was very worried about because they had already suffered frostbite with their previous owners. Chickenhouse [18'x16'] is easy, throw a couple of heat lamps in there at opposite corners of the building and it keeps it up above freezing fairly well. Ducks and geese have deep shavings on the floor and a heat lamp high enough up they can't reach it. Because their insulating isn't finished, this building has temps that vary greatly but there are enough of them to keep each other warm. My thoughts, I have read extensively on the pros and cons of heating your houses. Things like last night make me think there has to be a way that is safe, doesn't require electricity, and could be a simple build for the DIY person. I am tending towards a rocket furnace. I don't have it all worked out yet but I know this would be set up outside of the buildings with ductwork or water pipes, not sure which route to go, running to each house, the furnace itself would be bermed with dirt to provide heat mass and the heat collected either with water, for a thermo syphon system or a sand/rock filled plenum, which would give off heat for long periods that would be allowed to rise into the buildings by convection. Anyone else set up a system they can use during extremes? I'd be very interested in hearing about what you use!