EGG PRODUCTION 



291 



and future heavy laying, and so gives him little concern ; retarded 

 laying is a matter for serious consideration. Although, as has just 

 been stated, laying begins normally with cessation of growth, normal 

 cases are in a minority. In a majority of cases laying does not begin 

 for some time after the bird is full grown. If the delay is only a few 

 weeks it hardly attracts attention, and may be explained either on 

 the ground that development was only seemingly complete, or that 

 a brief period must elapse after physical growth is completed before 

 the period of regular laying can begin. But when laying is retarded 

 for several months, as it often is, such explanations will not suffice. 

 Causes of retarded laying. The things which affect growth and 

 those which affect laying after it has begun are the common causes 

 of failure to begin to lay at maturity. Little has been done in the 

 line of scientific investigation of the subject, but ordinary observa- 

 tion indicates some of these causes, and suggests the need of inves- 

 tigation to determine how circumstances affecting the development 

 of the body affect the development of the reproductive organs. 

 From the commonly observed facts some reasonable general in- 

 ferences may be drawn. 



1. A check to growth at any stage may retard laying at 

 maturity. Many birds (not only individuals but flocks of all 

 sizes) do begin regular laying promptly upon attaining full bodily 

 development. When the situation in a stock of birds of the 

 same breeding is irregular in this respect, it will usually be found 

 that the birds which lay normally are those which have grown 

 without interruption, and that when growth has been in any way 

 retarded, the beginning of the laying period is retarded. (Appar- 

 ently, influences unfavorable to the development of the body are 

 still more unfavorable to the development of the reproductive or- 

 gans.) It is not unusual to find May-hatched pullets laying earlier 

 than their sisters a month older, and equal or superior to the earlier 

 pullets in development at the beginning of egg production. The 

 difference is explained in most cases by unfavorable weather in 

 April and early May. 



2. Any disturbance affecting the habits, nutrition, or comfort 

 of a bird at any previous stage of life may retard laying at ma- 

 turity. That such disturbances so affect and check laying when 

 the reproductive organs are functionally active (or beginning to be) 



