PROGRESSIVE POULTRY CULTURE 37 



It is thus that the poultryman, calling to his aid 

 all of the influences of Environment, Exercise and 

 Heredity that he can, seeks to develop a strain or family 

 of fowls that will lay eggs out of season and yield many 

 more eggs than usually are produced. It is consider- 

 able of a step in variation for a fowl to lay ten dozens 

 of eggs instead of one or two dozens in a year and some 

 further variation has taken place when the fowl lays 

 over two hundred eggs annually. 



It has taken a long time to produce the variations 

 expressed by the many breeds and varieties of do- 

 mestic fowls existing to-day which originally came 

 from the little wild jungle fowl of India. 



Variation may operate against the desires of the 

 poultryman bringing him disappointment rather than 

 delight. His birds may deteriorate rather than improve 

 in useful traits, especially if, through his carelessness 

 or ignorance, the surroundings of his flock are unfavor- 

 able. Such influences tend to cause variations which 

 detract from the profits of poultry keeping although 

 they may enable the fowls themselves to survive rather 

 than succomb to their environment. 



Climate. Temperature influences the fowls and 

 gradually causes variation. Warmth and consequent 

 comfort, resulting from proper shelter or a congenial 

 climate, encourages breeding and hence tends to increase 

 of numbers. Cold weather has an opposite effect, tend- 

 ing to prevent or postpone propagation. Here is an 

 important reason why hens ' hesitate to lay eggs in win- 

 ter. Egg-laying is an act of breeding. Each egg is 

 intended to produce a chick. When coldness causes 

 discomfort to the fowl it stops breeding operations and 

 devotes its energies to gaining body comfort. The blood 

 instead of going to manufacture eggs, furnishes more 

 fuel to keep up the body temperature. 



When coldness and dampness both afflict the fowls 

 and lack of ventilation cuts off the liberal supply of 

 oxygen, the combination of evil influences is usually 

 fatal. A new hen-house, tightly built, not properly dried 

 out and unventilated, has often provided a calamitous 



