THE INCUBATION OF HENS' EGGS 195 



suspicion. Jackson' found in a test where 440 eggs were 

 incubated in several groups, and lialf of eacli grou]) were 

 washed and lialf unwashed, that the unwaslied eggs liatched 

 12.5 per cent more vigorous chicks, than tlie washed eggs. 



Where eggs are broken in a nest and their contents smeared 

 over other eggs in the nest, it is very likely to prevent the 

 latter from hatching. In this case, washing appears to be 

 the lesser of two evils. 



In cases where it seems advisable to disinfect hatching 

 eggs, they should be dipped, instead of sponged or washed, 

 and allowed to dry without being rubbed. 



Resting Shipped Eggs. — Persons shipping eggs any distance 

 for hatching, frequently furnish instructions to the effect 

 that the eggs are to be unpacked, placed in a normal position 

 on their sides, and rested twenty-four hours before setting, 

 for the purpose of allowing the germ to resume its normal 

 position at the uppermost point of the yolk. Such resting 

 does no harm beyond increasing the holding period by so 

 long, but it remains to be proved that the eggs cannot rest 

 just as successfully in an incubator or under a hen as in 

 any other place. 



Apparently the only data on this point are those given by 

 Gowell- who shipped two similar lots of eggs a distance of 

 514 miles. From the lot of 65 eggs which were rested twenty- 

 fovir hours, 15 chicks were secured, while from the other lot 

 put immediately into the incubator 22 chides were obtained. 

 The numbers are too small to be conclusive but there ap- 

 peared to be no marked advantage at least, in resting the 

 eggs. 



Warming Hatching Eggs. — Under natural conditions all 

 eggs but the one laid last are of necessity held for hatching 

 for a longer or shorter time. Jackson^ observed that very 

 often the oldest egg in a clutch was frequently the first to 

 hatch. He further noted the fact that in lajing, the average 

 time spent on the nest was approximatel_y sixty minutes. 

 As a result of two j-ears' work, he found that by placing 

 eggs, being held for hatching for a consideratile time, under 



' Pennsylvania Bulletin No. 120. 



2 Maine Station Report, 1902. ' Ibid. 



