The Youngblood family has six 40 foot by 400 foot chicken houses in Southwestern Missouri. As rising propane prices began eating into the farm’s cash flow three years ago, brothers Bruce and Doug Youngblood decided that there had to be a less expensive way to heat their houses and stay in the chicken business.

A neighboring farm raises fescue for seed and round bales the fescue straw. This farmer had no market for the straw. Bruce and Doug saw the straw as a potential heat source, and designed and built a furnace to burn the straw. The bales are around four feet wide and six feet in diameter, so the furnace’s fire box is cylindrical and is seven feet in diameter and 10 feet deep. Each end of the fire box has a door and with both doors open, a skid loader is used to put a new bale in and push ashes out the other door into a chute at the same time. The fire box can hold two round bales at one time.

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Hay furnace can burn round bales of hay, straw or corn stalks.

Bruce said that a magazine article about a farmer in Canada who had designed and built his own furnace to burn flax straw to heat his chicken houses provided the original idea for their furnace. The Youngbloods retired their first prototype furnace a year ago and put an improved furnace design into use on their farm. After a year of use, the Youngblood’s are pleased with the performance of the furnace, and they have applied for some patents on the design of the stove.

Doug estimates that the furnace generates around 2 million BTUs when operating at capacity. Water is heated and stored in a four thousand gallon tank which surrounds the stove. Water is piped to the six chicken houses where it moves through radiators which have fans blowing over them to transfer the heat into the house. The Youngblood’s system is set to heat the water to 150 F and forced air is used to accelerate the rate of combustion when more heat is required. Thermostats in the chicken houses provide the cue for the poultry house controllers to start the pumps to circulate the hot water. Bruce and Doug have added an external insulated 4,000 gallon water tank to the heating system on their farm to improve the operation of the furnace. In winter months, Doug estimates that the hay furnace reduces the farm’s propane usage by between 75 percent and 80 percent. During the rest of the year, the hay furnace can provide up to 95 percent of the heat needed in the broiler houses. In the non-winter months, Doug said that the hay furnace is burning for about the first four weeks of a flock’s life.

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In 2006, the Youngblood’s total propane bill was $19,300, and Bruce said that neighboring growers with similar houses had gas bills of $60,000. Doug said that they burned 350 round bales that year and that they paid $10 per bale. So the hay furnace saved them around $36,500 on fuel.

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Computer controlled fans force air into the fire box and
speed up or slow down combustion to maintain
the temperature in the hot water tank at 150F.

Bruce said that they have begun building stoves for some neighboring growers. The cost of the stove itself is in the $40,000 to $50,000 range, Bruce said. A radiator and fan unit needs to be placed every hundred feet of poultry house length. Bruce estimated that a typical four house broiler farm could be outfitted with a hay furnace and all of the required fans, radiators, piping and pumps for between $70,000 and $80,000. The stove with the one 4,000 gallon tank would be sufficient for a four house farm, according to Bruce.

One drawback of the system is that a round bale only lasts around five to six hours. So even if the stove is loaded with hay right before the grower goes to bed, the propane stoves will probably be on in the morning during the winter. The hay must be kept dry, so storage for the bales must be available. Doug said that future emission requirements may mean that a scrubbing system will need to be put on the furnace’s exhaust. The stove burns cleanly when it is operating at temperature, but it does smoke for a few minutes on start up, according to the Youngbloods. Doug and Bruce said that they have successfully burned other bailed items like corn stalks and even thistles. They say that you can burn just about anything, as long as it is dry.