Talk about alternative heat for brooding, aside from brooding bulbs or the gas brooders...people are amazed and surprised when we say they can burn things inside a drum or tin can.
You can use rice hull which will give you carbonized rice hull after. Depending on what is abundant in your area, you may use coconut husks, coconut shells, wood that gives you charcoal later, or charcoal itself.
The point it to have a heat source that is available, convenient to use and economical :)
Most are scared about the chickens getting suffocated by the smoke.
Did you ever see smoke that blows down?