1905.] 



Ventilation of Poultry Houses. 



439 



The experiment lasted from December 10th, 1904, till March 

 29th, 1905, and during that time the five hens in house No. 6 

 laid 194 eggs, an average of 38*8 per hen ; while the ten hens 

 in house No. 11 laid 285 eggs, an average of 28*5 per hen. It 

 appears, then, that the hens in house No. 6 laid more eggs than 

 those in No. 11, earning 4s. a head during the fifteen weeks in 

 one Case, as against 3s a head in the other — a result strongly in 

 favour of No. 6. 



There is no reason to believe that this result was due to any 

 accidental causes ; the difference in the two houses seems rather 

 to be due to some fundamental factor, and Messrs. Robinson and 

 Russell, by whom the experiments were carried out, having 

 ascertained that there was practically no difference either in 

 the purity or temperature of the air, suggest that the true 

 Explanation lies in the amount of heat lost by the birds. Air 

 passing through the house and coming in contact with the 

 warm body of the bird becomes heated and escapes, only to be 

 replaced by cold air. Each particle of air as it passes robs the 

 bird of some heat, causing the combustion of more food as fuel 

 to maintain the necessary temperature of the body. As has 

 been stated, the air changes eight times per hour in house 

 No. 11, and only four times per hour in No. 6. The result is 

 that each bird in the former house is robbed of its heat by twice 

 as many air particles as in the latter, and must therefore use 

 more of its food for the purpose of keeping up its temperature, 

 and, of course, if the food is consumed in this way it is not 

 available for the production of eggs. 



The conclusion therefore arrived at is that, although the 

 purity of the air may be maintained with a larger number of 

 fowls in a house of the floorless type by ground ventilation, it 

 is better for the birds and more profitable to the owner to give 

 them ten cubie feet in a house provided with a floor or resting 

 on the ground, than five cubic feet in a house with ground venti- 

 lation. If the house is of the type provided with wheels and 

 ventilated from below, it is better, during the winter at any rate, 

 to let it down on the ground. The full space prescribed above 

 should, however, be given. 



It is pointed out that it is absolutely essential to secure top 

 ventilation. The houses as supplied by the makers to the 



