22 The Business Hen. 



frequently while the hen is on the nest. A color pigment is sometimes 

 secreted with the shell-making liquid, which gives to eggs their character- 

 istic colors. The color of the shell is largely an individual characteristic, 

 and remains practically constant with the individual, except that the egg 

 shell gradually fades in color toward the end oi the laying period. This is 

 particularly noticeable in comparing the first and the last eggs laid by 

 turkeys. The shell-making fluid appears to be secreted by tiny ducts, 

 which leave their impression by numerous fine depressions or pores in 

 the egg shell, which can be easily seen by close inspection. The importance 

 of providing mineral matter in the form of cracked oyster shell, mortar 

 and bone is seen in the fact that if the hen lacks these materials or through 

 debility cannot assimilate them, her eggs will be soft-shelled. Naturally, 

 when the egg production has drained her system of this material, her 

 appetite craves it, and if it is not otherwise supplied, she will instinctively 

 eat the egg shells. This is the most common cause of egg eating. 



When the egg rests in the "cloaca," Fig. 2 (4), before being laid, it is 

 covered with a secretion that assists in the depositing of the egg, which 

 when dry gives the shell its natural fresh appearance, and which undoubt- 

 edly has much to do with controlling the evaporation of the egg contents. 

 Therefore eggs for hatching should not be washed unless it be to remove 

 dirt which would materially stop the pores in the shell. This oily coating 

 is particularly apparent on duck eggs. 



It is to be doubted whether a hen can voluntarily stop the formation 

 of an egg up to the point of its completion. But she can retain the egg 

 at will for considerable time thereafter. It is. perfectly certain, however, 

 that improper feeding, neglect, fright or any condition that interferes with 

 digestion or peace of mind will stop the process of egg-making in any 

 of its stages. Frequently the white is deposited without yolk or shell. 

 It is very common to find eggs devoid of shell, and occasionally a yolk 

 will be laid without shell or albumen. It is not uncommon to find an egg 

 with white and shell complete without the yolk. In rare instances a per- 

 fect egg has been found within an egg. This is brought about by the 

 completed egg being forced back by injury through the portion of the 

 oviduct where additional albumen is secreted and then returning to the 

 place where a new shell is deposited. When the egg evaporates, the outer 

 membrane, Fig. 3 (3), continues to adhere to the shell, while the inner 

 membrane follows the contents of the egg as it shrinks in size, thus form- 

 ing the air space, which is usually at the large end of the egg, occasion- 

 ally on the side and rarely on the small end. 



The shape of the egg is determined by the form of the mold in which 

 it is cast, which differs with breeds, varieties, and even with individuals 

 of the same strain. The form of egg peculiar to an individual remains 

 practically constant, so much so that one can pick out an egg from certain 



