220 POULTRY PRODUCTION 



it to 102° F. on a level with the top of the eggs. When this 

 temperature is reached the flame should be so adjusted that 

 the temperature will be maintained with the damper disk 

 hanging an eighth of an inch above the heater. This allows 

 a reserve of heat for the regulator to make use of in case of 

 a drop in the incubator-room temperature. This condition 

 should be maintained for at least twenty-four hours before 

 putting in the eggs, in order to make sure that everything is in 

 good running order. The eggs should then be put in and the 

 incubator left closed for two days. 



Temperature. — ^The temperature should be held at 102° F. 

 during the first week, 103° the second week, and until the 

 eggs begin to pip, when it may be allowed to go to 104°. 

 Under no circimistances should it be allowed to run above 

 105°. 



Moisture. — At the same time that the eggs are put in, 

 moisture should be supplied. The amount depends upon 

 local climatic conditions. In dry sections or during a drouth, 

 a shallow pan, the size of the floor of the nursery, filled with 

 sand and puddled with water, should be used. Such an 

 arrangement is usually referred to as a sand tray. 



Where there is a fair amount of moisture in the air a sand 

 tray half as large may be used, and in damp sections, or 

 during a wet season, the sand may be left out and only 

 water put in. In any case the water should never be warmed 

 more than is barely necessary to take off the chill. 



The common means of gauging the amount of moisture to 

 be supplied as the period advances is the size of the air cell. 

 A more reliable means is weighing the eggs, as suggested 

 by Atwood,' and comparing the evaporation loss with the 

 calculated normal loss for the same number of fertile eggs. 

 The ordinary person usually does not judge the relative 

 size of the air cell very accurately. It is an excellent plan to 

 use a hygrometer or wet-bulb thermometer in connection 

 with the weighing. Where their relationship in a given 

 locality is once established the weighing may be dispensed 

 with and the wet-bulb temperature used as a guide. 



' West Virginia Bulletin No. 98. See page 209. 



