POULTRY NOTES. 43 



line showing the price of eggs in the same months. This price 

 curve is given by the dotted Hne and is based on New York 

 market quotations for the year 1907 taken from the April, 1908, 

 Crop Reporter. It will be seen that as is to be expected, the 

 price line looks very much like the egg production line turned 

 upside down. In the months when the egg production is high, 

 the price of eggs is low, and vice versa. It is of interest to note 

 that while the general form of the price curve is similar to that 

 of the production curve turned upside down, yet there is a lag 

 of the price curve behind the production curve. The explana- 

 tion of this lag, of course, lies in such factors as rate of ship- 

 ment, movement of sold storage eggs, and similar things. 



It is usual to attribute the most strikingly marked features of 

 such egg production curves as that given in Fig. 5 to climatic 

 influences. It is commonly said that when it begins to warm up 

 in the spring the hens begin to lay better and the relationship 

 between climate and egg production is thought to be a causal 

 one. There is a tacit assumption that it is because it gets 

 warmer in the spring that the hens lay more eggs in the spring. 

 As a matter of fact there is strong evidence to show that the 

 shape of the egg production curve is based upon deep seated 

 biological factors rather than directly on these cHmatic changes. 

 It is not the place here, to go into an extensive discussion of the 

 evidence on this point. Such evidence will be presented later in 

 another publication. 



Whatever the cause of the unequal seasonal distribution of 

 egg production may be the fact of its existence must be granted 

 by all. If this fact be granted it immediately raises the question 

 as to whether it will not be advantageous in studying the prob- 

 lem of egg production in general to endeavor to use a time unit 

 which conforms to the natural periodicity displayed by hens. 

 In recent years it has been the custom in the discussion 

 of egg production to make the unit one year. This custom has 

 been followed in the work of this Station ; in the egg laying com- 

 petitions in South Australia, which have excited world wide 

 interest, and by many other institutions and experimenters. It 

 •is safe to say, however, that all experimentors and students of 

 the subject of egg production have felt that the year was not 

 in all respects an ideal unit for such studies. A serious objec- 

 tion to it is immediately apparent if one makes a close study of 



