Mar., 1938] Electric Brooding of Chicks, II. Heat Requirements 19 



A disc of %" insulating board practically the same size as the 

 brooder was secured. A full 60-foot length of 400-watt, soil-heating 

 cable was fitted into a spiral groove cut in the upper surface of the 

 board. Another disc with exactly the same area but of 1/4'' hardboard 

 was placed on top and the two firmly bolted together. The edge was 

 bound with brass linoleum binding. A wafer thermostat was mounted 

 in a metal electrical outlet box, (attached to the pad), in such a man- 

 ner that the wafer was practically in contact with the surface of the 

 hardboard, forming the top of the pad. A socket for a pilot light was 

 inserted in the end of the same box and cut into the circuit. A cord 

 and attachment plug were used so that the pad could be inserted in a 

 metered circuit separate from the brooder circuit. 



II. Brooder Extensions 



Brackets were made of strap-iron and bolted to the edge of the 

 brooder. On these was bolted a 12" ring cut from y>^' insulating board 

 and a 6" curtain was tacked to the outer edge of the extension ring. 

 Picture-wire braces were stretched from the outer edge to the apex of 

 the brooder to stiffen the whole assembly. 



It was found during the first run that the moisture was absorbed 

 by the insulating board to such an extent that it became soft, would not 

 hold the curtain, and even broke up along the outer edge. 



For the next two runs the extensions were constructed of %" ply- 

 wood bolted to the brackets. The plywood, although it warped some- 

 what, stood up much better throughout the run. 



III. Wire Floor 



A circular frame of strap-iron slightly smaller than the brooder 

 was constructed and well braced. To this frame legs were bolted to 

 raise the top surface 2" above the floor. 



The frame was covered with 1" mesh hardware cloth extending 6" 

 beyond the frame all around, and the extension bent down to form a 

 ramp. A circular piece of 14" mesh hardware cloth was then cut and 

 fastened over the V mesh. 



The I/2" mesh wire was used for the first few weeks ; then by simply 

 clipping the wire ties holding it to the other, it was removed, and the 

 I'^-mesh was left in place for the rest of the run. 



Results of the Experiment 



The floor temperatures obtained from the use of these methods are 

 shown graphically in Figure 7. These may be compared with the tem- 

 perature of the regular house floors the first 4I/2 days, as shown by 

 Figure 2. 



It will be noticed that the opposing temperature in 1936 was quite 

 rigorous, reaching 10 degrees and 20 degrees below at night, spending 

 much of its time at zero or slightly above, and at no time going above 

 -f 20 degrees F. 



A characteristic that has repeated itself consistently in all tem- 

 perature curves in 2,800 daily records has been the definite correlation 

 of the brooder floor temperatures with outside temperatures. One of 



