INCUBATION 103 



cates the temperature at the center of the egg, which 

 should be 100.5 F. When the ordinary or regular type 

 of thermometer is used, and when the bulb rests at or 

 near the upper outside of the egg, the temperature should 

 not go below 101 F. and not much above 103 F. 



The statement made that the atmosphere should be 

 changed sufficiently often to carry off the waste gases 

 refers to proper ventilation. In writing of this, Pro- 

 fessor Lamson says that by the use of specially con- 

 structed apparatus it was shown that the ventilation 

 required in the incubator to secure the best results in 

 living chicks consisted in a change of 5 cu. ft. per hr. 

 for each 50 eggs. Where the change of air exceeded 

 10 cu. ft. per hr. for each 50 eggs, the hatch began to 

 run down, and when the air change was reduced to y\ cu. 

 ft. per hr., only a very small percentage of chicks were 

 hatched. 



As a result of many experiments, it has been shown 

 that hen-hatched chicks weigh 1.258 oz. ; that incubator- 

 hatched chicks with maximum moisture weigh 1.184 oz. ; 

 that chicks hatched in incubators with a medium amount 

 of moisture weigh 1.159 oz.; and that chicks hatched in 

 non-moisture machines weigh 1.072 oz. It has also been 

 shown that the minimum moisture in the incubator might 

 be 45%, while the maximum might be 70%. 



The weight of these chicks seems to indicate that to 

 have the greatest possible vigor in chicks a greater quan- 

 tity of moisture is required during incubation than is 

 present in the average incubator. For these reasons, 

 considerable effort has been made to find some means of 

 introducing moisture into machines during the period of 

 incubation. Among the devices used are pans of water 

 or pans of sand moistened with water and placed under 

 the egg tray. Another way is by sprinkling the eggs 

 with water morning and evening during incubation as 

 clothes are sprinkled with the hand or by means of 

 sprays such as are used by druggists or florists. 



An excellent method of applying moisture is to have 

 pads made of burlap or felt, and cut to fit under the 



