if you are able to make hot water bottles place them in the brooder with a towel over them. Thats what I did last spring when we lost our power, I have a natural gas stove so I could heat up water and just put it in like a milk jug or I used large liter pop bottles, dont get the water to hot so it melts the plastic, just nice and warm to snuggle with. I sat them in the brooder and covered them with kitchen towels and my 4 little girls just snuggled up to them. I would change them out before they got to cold and they made it for 10 hours that way!!