Mar., 1938] Electric Brooding op Chicks, II. Heat Requirements 



15 



Effect on Floor Under Brooders 



The upper curve in Fig. 3 (1933-34 tests) shows the temperature of 

 the floor directly under the brooder taken simultaneously with the tem- 

 peratures shown in the two lower curves of the air under the house and 

 the outside air. 



The time at which the upper curve begins to rise each morning coin- 

 cides with the time at which the outside air and under-house air curves 

 begin to rise. This, as suggested before, we believe to be due to the 

 action of the sun's heat. The angles of the outside air and under- 

 brooder floor temperatures are steep and reasonably parallel between 

 mid-morning and mid-afternoon. The rise in under-brooder floor 

 temperature continues until midnight with some abrupt interruptions. 



During this period before midnight the chicks have huddled and 

 settled down for the night. Chick movement and restlessness, de- 

 scribed in Circular 46 and later in this report, begin as the tempera- 

 ture increases, due to an apparent effort by the chicks to find the most 

 comfortable degree of heat. The downward curve of the outside air 

 temperature from mid-afternoon to this midnight point is directly op- 

 posite to the rising temperature of the floor under brooder. Regu- 

 larly at or near this midnight point the floor curve starts down steeply. 

 This downward slide starts almost immediately after the highest point 

 of temperature has been reached at night, and can be ascribed to the 

 fact that the chicks break their huddle to relieve temperature and air 

 conditions. 



There is a directly traceable relation and beneficial effect of the 

 sun and outside air temperature on the rising parts of these three 

 curves. No correlation seems to exist between the air under-house 

 temperature and the floor under-brooder temperature for the balance 

 of any twenty-four hour period. This strengthens our assumption 

 that chick movement causes the sudden downward trend of the floor 

 temperature curve from midnight to early morning. 



Table IV. Brooder and Total Floor Area Relations. 

 Total Chicks Per Brooder, 225 



O C 

 ^ P 



0) 



0, 

 >, 



per cent. 



