THE INCUBATION OF HENS' EGGS 2]?> 



Table XXXIII. — Effect of no Moisture, Medium Moistujie, and 

 Maximum Moisture. 



Medium IMaxiiniim 



No moisture. moisture. moisture. 



Number of eggs set . . . 700.0 701.0 712.0 



Number of eggs hatched . .3.30.0 424,0 420.0 



Percentage of eggs set hatched . 47.1 60.5 59.0 



Percentage of fertile eggs hatched 69.1 82 . 1 77.3 



In this case the relative humidity averaged 4S.7 i)er cent 

 in the non-moisture macliines, 55.3 per cent in the medium 

 moisture, and 64.7 per cent in tlie machines having the 

 maximum supply of moisture. The corresponding wet-bulb 

 temperatures were .S4.5°, 87.0°, and 91°. At the same time 

 the relative humidity of the room where the incubators 

 were operated ranged from GO per cent to No.l per cent, 

 with an average of 73.4 per cent. 



In other observations made in Utah, where it was 

 much drier and the relative humidity of the room where 

 the incul)att>rs were operated was only 45.5 per cent on 

 the average, Dryden' found that the maximum moisture 

 machines had a relative liumitlity of but 55.5 per cent and 

 gave the best results. 



Referring to the Oregon results, Dryden says: "In com- 

 paring the weighings of incubator and hen eggs, the eggs 

 in the non-moisture incubators lost 1'2 per cent more weight 

 than the eggs under hens, but the moisture machine showed 

 less loss. The results show that the dry machines "dry 

 down" the eggs too much, while the maximum moisture 

 machines show too little evaporation. Between tlie mcdiimi 

 moisture machines and the hens there is considerable dilfer- 

 ence. It is a question, however, if less eva]ioration of the 

 eggs under the hens would not be desirable. It has never 

 been demonstrated, to the writer's knowledge, whether it 

 is better to set the hens on the ground than on dry nests. 

 On the whole the result of the weighings agrees with the 

 results of the hatching in showing the necessity of supplying 

 a certain amount of moisture to the incubator." 



Ilannas- fdund frcim a large nunibiT (jf meosnreHiciits that 



> Oregon Bulletin No. 100. 



■^ Jour. Am. Assn. Inst, and In\"est. in Puul. Hubl"). val. v, No, 10. 



