The changes in the proportion of low producers is in striking contrast with our figures, for since 1913 they have been completely eliminated. The high producers have increased steadily until in 1920 more than a third of the Rhode Island Reds submitted laid 210 eggs and more. This is twice as great as the highest proportion of high producing fowls of this breed ever entered in the Storrs contest. The result is the attainment of a much higher average production and much greater uniformity by the birds in the English contest. THE SEASONAL DISTRIBUTION OF EGG PRODUCTION GENERAL CHARACTER OF EGG PRODUCTION IN THE SEPARATE breed MONTHS A description and analysis of fecundity in this or any requires for its completion a consideration of individual variation in the number and proportion of eggs laid in the months and seasons of the year. The following section will, therefore, discuss the average monthly and seasonal egg production and the variability in respect to egg production in different periods. In addition it will present the evidence bearing on the existence of cycles of egg production in Rhode Island will attempt to determine the general trend of changes in seasonal distribution of egg production in the nine years which the records cover. Reds and VARIATION IN MONTHLY PRODUCTION The data for a study of egg production in the various months of the pullet year are contained in Appendix Table IIa and IIb. In Table IIa is given the frequency distribution of the total number of pullets for the nine years, showing the number of birds laying 0, 1, 2, 3,........ 30 eggs in each month. The monthly means and variation constants have been calcu lated directly from the ungrouped frequency distributions in this table. In Table IIb, the frequencies of Table IIa are stated as percentages of the whole number of birds present. From this table the proportion of the flock laying a given number of eggs can be read off directly. Thus the proportion of the flock laying zero eggs in November is 67.31 per cent, for December the proportion is 45.58 per cent etc; or in October 31.01 per cent of the flock did not lay any eggs; 4.77 per cent laid one egg each, 2.39 per cent laid two eggs each etc. The general character of changes in monthly egg production are evident in these tables and they resemble the changes in other breeds and poultry in general, which have long been familiar to poultrymen. For convenience in reference, the proportion of birds not laying in each month has been extracted from Table IIb and is shown in Table 12. In the early months of the pullet year (November, December, etc.) most of the birds are not laying; actually in the population with which we are dealing only about a third have begun to lay in November. The drop in the number of birds not laying is rapid and steady from November to March at which time practically all of the birds are laying from one to thirty eggs per month. This condition obtains through the month of August although a small proportion of the flock ceases to lay in June, July and August. After August many more birds cease to lay until in October roughly about one-third of the flock has stopped laying. The conditions at the beginning and at the ending of the year are, therefore, reversed, since in November the proportion of layers to non-layers was about one to two while in October this proportion is two to one. It is also evident from Table IIb that the forms of the curves describing egg production in the different months are in general similar. Each monthly distribution contains two kinds of birds: low producers laying from zero to something less than ten eggs in the month, and high producers laying from eighteen to twenty-three or four eggs in the month, with of course all variations in between. The probable separateness of these two classes is indicated by the tendency of the distribution for each month to be bi-modal, the lower mode at or near zero in each month, about which are grouped the low pro 62 234 493 659 846 1157 1104 1079] 128 279 748] 1919 797 1342 2185| 2202| 2100 1848| 1609|1015| 20838 PERCENTAGE DISTRIBUTION OF TOTAL EGG PRODUCTION BY MONTHS AND YEARS. F TABLE 5 DISTRIBUTION OF TOTAL EGG PRODUCTION BY MONTHS AND YEARS. Nov. Dec. Jan. 56 95369 719 Feb. Mar. ཧཱུྃ ། སྒོ June July Aug. Sept. Oct. 917 1137 1119| 867 783 766 731 657 510 1168 1243] 808 13284 8.29 10.58 13.11 12.91 10.00 9.03 8.84 1915 183 2.20 5.27 7.28 9.35 11.88| 12.69 11.85 10 34 9.32 8.09 7.14 4.60 100.01 1916 | 188 3.05 4.70 6.73 8.93 12 66| 11.70| 11.21 9.83 9.12 7.95 8.05 6.10 100.03 | 129 1.92 4.16 5.74 8.36| 12.72] 11.85| 11.97 10.49 9.04 9.66 8.68 5.41 100.00 7.27 8.35 10.74| 12.19 13.21 9.76 8.23 8.80 9.35 6.09 99.97 1919 126 3.79 5.08| 6.28 8.03 11.88| 12.09| 12.43 9.84 8.90 8.96 7.80 4.92 100.00 Total |1132| 2.31| 4.65 6.65 8.60| 12.13| 12.04| 11.79 10.15 9.29 8.80 8.11 5.48 100.00 This table contains the data of Table 5 stated in the form of percentages for direct comparison between months and years. It ducers; the upper mode, determined roughly by inspection, at or near eighteen in November, twenty-one in December and varying between these points or slightly higher or lower in the other months. The principal constants describing variation in monthly production are given in Table 7. (a). Mean production. The mean or average production of eggs parallels roughly the proportion of birds laying. In November the average production is 3.55 eggs. This is probably somewhat lower than the November average for similar pullets which have not undergone the sudden change of conditions and the hardships of transportation to which the contest birds have been subjected. The November average probably cannot be used accurately as a general standard for Rhode Island Reds which have made their records under other than contest conditions, but that changed conditions have had no serious effect on the general character of egg production is witnessed by the close correspondence in this respect which was found by Harris and Goodale (1923) between contest and experiment station flocks. The course of mean production after November and possibly December is probably normal for Rhode Island Reds of good breeding. The changes in production are shown graphically in Fig. 5 which with the exception noted may be taken as a standard for this breed under similar conditions. |