﻿24 BULLETIN 21, U. S. DEPARTMENT OF AGRICULTURE. 



INDIVIDUAL VARIATION IN FATTENING CHICKENS. 



A study of Table 12 and of the variation in the summaries of the 

 feeding experiments at the different stations shows that many fac- 

 tors affect the gains in fattening. Variation within a lot is due some- 

 what to the difference in the weight of the birds, but largely to the 

 difference in the ability of the individuals to take on flesh under the 

 existing conditions. This plainly shows how much variation exists 

 in this ability to fatten readily, and the influence which the weather 

 has in fattening. The possible error of conclusions drawn from small 

 lots in fattening experiments is readily noted, and this possibility 

 undoubtedly occurs under other poultry methods, as in the influence 

 of feed and housing on the production of eggs. The marked effects 

 of weather on fattening demonstrates the error which may occur in 

 direct comparison of fattening tests conducted at different periods of 

 the year, or in different seasons. 



Table 12. — Individual variation in fattening chickens. 



Number 

 of head . 







Average weight. 



Num- 

 ber of 

 days 

 fed. 



Per cent gain. 





High. 



Low. 



High. 



Low. 



Average. 



1,790 



1,400 



1,216 



1,880 



1,080 



768 



320 



600 



480 



320 



1.024 



512 



1,088 



768 



Roasters 



...do 



...do 





Pounds. 

 4.19 

 3.07 

 3.05 

 2.03 

 1.95 

 1.89 

 1.75 

 1.65 

 1.76 

 1.75 

 3 . 55 

 1.47 

 2.28 

 1.58 



Pounds. 

 2.58 

 2.53 

 2.70 

 1.43 

 1.62 

 1.69 

 1.23 

 1.50 

 1.40 

 1.61 

 2.72 

 1.34 

 1.11 

 1.47 



8 

 8 

 8 

 15 

 14 

 14 

 14 

 14 

 14 

 14 

 11 

 15 

 13 

 14 



Per ct. 

 36.4 

 25.9 

 27.0 

 55.0 

 63.0 

 56.0 

 45.0 

 53.0 

 39.0 

 43.0 

 29.0 

 63.0 

 67.0 

 45.0 



Per ct. 



4.5 



7.6 



9.0 



17.0 



18.0 



12.0 



36.0 



18.0 



31.0 



25.0 



7.0 



31.0 



11.0 



30.0 



Per ci. 

 13 

 14 

 14 

 27 

 29 

 36 

 39 

 38 

 35 

 41 

 18 

 44 

 35 

 37 



Springs.. 



...do.... 



Broilers. 



do 





..do 





...do.... 

 ...do.... 



Broilers. 

 Springs.. 

 ...do 





In the above work individual records were kept of each battery 

 containing 64 birds. The variation in average weight and in per 

 cent of gains was between batteries of birds fed under the same con- 

 ditions. The great variation in birds fattened under the same con- 

 ditions suggests the economical possibility of rejecting certain birds 

 in fattening. A very small per cent of birds called "rangers" were 

 graded out of the receipts at Station 1 and killed without fattening. 

 These birds consisted of black and feather legged stock, Leghorns, 

 and birds out of condition. All black and feather legged birds were 

 kept separate at Station 4 and fed only for a short period during the 

 early part of the feeding season. Much better results could be 

 secured in the fattening stations if only the best birds were selected 

 for fattening, although this would require extra skilled labor for 

 selecting, and involve a different and more complicated system of 

 handling the birds at the packing house. 



