306 EARL W. BENJAMIN 



type produced by the progeny, point directly to an easy way of improving 

 a commercial flock by careful selection of the eggs for hatching. The 

 results of this investigation show that a study of all the eggs produced 

 by the parent hen, such as would be possible only by trap-nesting, would 

 be more dependable than a selection of the incubated eggs alone; but the 

 latter method is found to be a possible way, as well as an easier and quicker 

 way, of obtaining good results. 



The fact that the size, the shape, or the color of eggs doe's not affect their 

 incubation record, leaves the poultryman free to select his eggs for hatch- 

 ing according to his own preference without its. affecting the percentage 

 of hatch. 



The old opinion that hens' eggs approach a definite standard, to which 

 they adhere more uniformly as the bird becomes older, is not borne out 

 by the results of those studies. From this work it seems that the variability 

 of a hen's production does not decrease as the hen becomes older. If 

 the indication shown here is a fact, it does away with one of the several 

 arguments which the poultryman has for using hens' eggs instead of 

 pullets' eggs for hatching. The work of Pearl (1909) with Plymouth 

 Rocks does not show agreemsnt with this theory. 



There S33m to b3 no gradual and consistent changes thruout the life 

 of the bird for any of the threo egg characters studied. Nearly all of the 

 changes noted occur between the productions of the first and the second 

 year. Since the eggs produced during the second year are nearer to the 

 mean for the entire life production of a bird kept for from thres to four 

 years, it would b3 expected, and was found generally, that the eggs 

 selected for incubation produced by hens two years old or older, gave 

 more consistent correlations than those produced by pullets. 



The positive relation of the size of the egg incubated to the size of the 

 resultant chick and mature bird, is of value to poultrymen who are inter- 

 ested in the production of either poultry or eggs. 



The inheritance of the characters studied is undoubtedly of the type 

 of a Galton regression. Much further study is needed in order to properly 

 analyze the unit factors, or physiological units, involved in the formation 

 of the broad practical characters here observed. Until further results 

 are available, however, the fact that certain general lines of inheritance 

 ars known gives breeders some evidence on which to base more work 

 for the improvement of their flocks. 



