90 POULTRY PRODUCTION 



develop when placed in an incubating teni])erature. Such an 

 egg is tlie equal of a fertile egg for food purposes, and very 

 much superior for preserving, shipping, or storage purposes. 



Freak Eggs. — There are various kinds of abnormal eggs 

 wliich aiii)ear in flocks of any size with more or less frequency. 

 The most common is the double-yolked egg, which is caused 

 in two ways: two yolks may develop in one follicle, and 

 escajtc, and be taken up by the oviduct at the same time and 

 wrapped in the same albumen, shell membranes, and shell. 

 A second way is by tlie jiretiiature rupture of a follicle, 

 which allows the yolk to cs<-a,pe into tlic body ca\it>'. This 

 yolk is sought out and taken \i\> by the o\iduct, often just 

 before or after another yolk is recei\ed from the ovary. 

 These two y(.)lks then trawl down the o\ iduct together, as 

 in the first case. In either case one or both of the yolks may 

 be fertile and de\elo]:) chicks, though these rarely hatch. 



Tlie so-called s<ift-shelled egg is usually one that has no 

 shell. Tills may l>e causetl by the sliell gland failing to func- 

 tion or by the ])crist;dtie constrictions becoming so violent 

 as to hurry the egg to exclusion, without allowing time for 

 tlie secretion and deposition of the sliell. 



When the shell material is first applied to the egg it is 

 plastic and the oviduct on the outside and the egg on the 

 inside together constitute a mould which determines the 

 shape of the egg. For some reason that part of the oviduct 

 which immediately surrounds the egg sometimes becomes 

 constricted, taking on what is termed an hour-glass form. 

 The result is that as the shell material hardens it takes the 

 same form, becoming what is called, for want of a better 

 name, a "dumb-bell" egg. 



Of quite common occurrence are the \ ery tiny eggs which 

 have no yolk. These are caused b}' some foreign substance, 

 as a clot of blood or a piece of detached membrane, finding 

 its way into the oviduct and travelling tlown in the same way 

 that an egg does. As it comes to the albumen secreting 

 portion, the gland is stimulated and secretion occurs, much 

 as though a }-olk were present. After being surrounded by 

 albumen the substance has the same history as a normal egg. 



It sometimes occurs that what appears to be a double- 



