ENVIRONMENTAL CONDITIONS 369 



It can then be stored away for use another year. This practice 

 is very satisfactory with early-hatched Leghorn chicks. 



Factors Affecting Growth. There are many factors affecting 

 the growth and development of chicks. They logically fall under 

 one of these heads: (1) Inherited characteristics; (2) environ- 

 mental conditions; (3) supply of feed. The last two might be 

 combined, but are considered separately because of the impor- 

 tance of feeding. 



Inherited characteristics determine the constitutional make-up 

 of the individual at birth. The effect of environment is constantly 

 acting and controls the development of inherited characteristics. 

 The pronounced difference in apparent size and strength of the 

 chicks at hatching time is largely due to inheritance, beyond the 

 control of the poultryman. The difference in size is very pro- 



FIG. 170. Growing poultry on free range is the most satisfactory method. Gasoline-heated 

 brooders are used on this farm. (Photo by Cornell University.) 



nounced in every hatch. Chicks of the same breed vary greatly 

 in size and weight at hatching time, and will not develop uni- 

 formly, some feathering early and others late. Some remain 

 dwarfed and never make a satisfactory development. Every 

 poultry raiser should practise a rigid selection from hatching 

 time to maturity, weeding out those lacking inherited vigor and 

 strength. Experiments show that such chicks never make profit- 

 able layers, sure breeders, or desirable market poultry, and the 

 sooner they can be disposed of the better. The best practice is 

 to select at weaning time all that are strong and vigorous, 

 placing them on the range in the developing houses. Take all 

 that are left and place them in suitable quarters, with restricted 

 range, if necessary, and force them for broiler purposes. They 

 may not make the best broilers, yet it is the most profitable use 

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