ANIMAL PRODUCTION. 273 



" During the period covered by tlie statistics all birds used for breeding 

 have been the offspring of mothers laying IGO or more eggs in their pullet year 

 and of fathers which were the sons of high-producing mothers. It is now pos- 

 sible to determine what have been the results of this extensive experiment in 

 selection. It is shown that the intensity or stringency of selection became rela- 

 tively greater during the progress of the exiieriment. though the absolute 

 standard of selection remained the same. It is further shown that there is 

 no evidence that the selective breeding practiced has improved the strain in 

 respect to egg production. On the contrary, the data show that (a) the mean 

 egg production has diminished during the experiment, (&) the variability in 

 egg production has remainetl unchanged, and (c) in the last years of the ex- 

 iieriment relatively slight environmental changes caused A-ery marked changes 

 in the flock productiveness. This is obviously inconsistent with the view that 

 any particular type of egg production has in any way been fixed in the strain 

 by the breeding. 



". . . The practical conclusion to be drawn from the results of this breeding 

 experiment seems to us to be clear. It is that the improvement of a strain of 

 hens in egg-producing ability by selective breeding is not so simple a matter as 

 it has been supposed to be. Nothing could be simpler than breeding from high 

 producers to get high producers. But if this method of breeding totally fails 

 to get high producers — in other words, if the daughters prove not to be like the 

 mothers in egg production — it can not fail to excite wonder as to whether the 

 simplicity of the method is not its chief (possibly its only) recommendation." 



Poultry notes, 1908, 11. Pearl and F. M. Surface {Maine Htu. Bill. JGo, pp. 

 2D-.'/S, figs. 5). — This bulletin is a report of the progress of the work in poultry 

 at the station in 1908. 



Some of the changes made for facilitating the work are the adoption of new 

 UK'thods in pedigree poultry breeding, and the erection of a hospital house for 

 sick poultry and for carrying out experiments of a physiological character. A 

 new type of trap nest has been constructed, and an improvement has been 

 made in ventilating the brooder house. Details for using liquor cresolis 

 compositus for destroying bird lice are given. 



A diagram of the seasonal distribution of egg production for the past 9 

 years "shows that beginning with an average production of between 4 and 5 

 eggs in November the line rises rather sharply to an average production of 

 nearly 12 eggs per bird in January. The line drops slightly in February, then 

 rises very sharply to a maximum of a little more than IG eggs per bird for 

 the month of March. From March on the line drops very steadily forming 

 almost a straight line until it reaches a low point in October." The form of a 

 price curve platted on the same diagram is similar to that of the production 

 curve turned upside down, yet there is a lag of the price curve behind the pro- 

 duction curve. Examples are cited to show that the value of a bird for egg 

 production depends upon the season the eggs are laid as well as upon the 

 number of eggs. One bird laid 193 eggs during the year, which were worth 

 $4.24; another bird laid 184 eggs, but were worth $4.8:5, as a larger percentage 

 of them were laid when eggs w(n-e high. It is the purpose at this station to 

 develop a breed which will lay in the winter season. 



A method is proposed f(»r estimating egg production on a percentage basis 

 as follows: "The measure of an individual lum's egg production in any given 

 time lyay be taken to be the percentage which the number of eggs actually laid 

 is of the maximum number of eggs which might have ))een laid by the indi- 

 vidual in this given length of time, assuming the production of on(> egg a day 

 to be the maxinunn of which a hen is cai>able." For (he iiurpose of easily 

 calculating this percentage a table is presented which shows the maximum 



