9 8 



sary to good egg-production as pure food and pure water. Damp air 

 may be removed by ventilators, which will necessarily make the house 

 a little cooler because cool air enters when the warm air escapes. Pure 

 air, however, is of vastly more importance than warmth, though both 

 are desirable. The principle involved in ventilating a house is that 

 warm air rises and cool air settles. It thus becomes easy to secure a 

 change of air when a contrast between the outside and inside tempera- 

 tures can be secured. This, however, must be accomplished without pro- 

 ducing draughts over the fowls, especially while roosting. The best 

 way yet found to accomplish this result is to make the house absolutely 

 tight on all sides except the front, leaving that comparatively open. The 

 openings should be covered with loose muslin or narrow-mesh wire 

 during the stormy weather and on cold nights. 



If a ventilating system is to be installed, the best ventilator is one that 

 has an out-take near the floor, with a tight wooden shaft leading up 

 through the warm air of the house to the roof and out at the peak. The 

 wood not being quickly affected by cold, will not be so likely to cause 

 countercurrents of air in the shaft. The in-take air should be received 

 from the bottom on the outside and conducted to the ceiling before 

 being allowed to enter the room. (Fig. 35.) This avoids direct draughts 

 and causes the circulation necessary for the removal of the moisture. The 

 less the difference between the inside and the outside temperatures and 

 the quieter the air the more difficult it is to ventilate. The tighter and 

 the warmer buildings are made, the easier they are to ventilate. The 

 larger the amount of air space the less need there will be for ventilators, 

 provided there is a change of air through windows or doors during the 

 day. (Consult King on ventilation in " Physics of Agriculture.") 



Poultry must not be allowed to suffer from cold. This is particularly 

 important at night, when the body is less active. The great difference 

 in production between summer, when hens naturally lay the most eggs, 

 and winter, when they always lay the least eggs, is due to the tempera- 

 ture and the sunshine. Therefore, we must build our poultry houses so 

 that we can overcome this condition as far as possible, consistent with 

 cost and good ventilation. 



It will require a perfect system of ventilation and considerable per- 

 sonal attention to keep the air in a poultry house as pure as it is outdoors. 

 It may be found advisable, therefore, in some instances to adopt the 

 scratching-shed plan of house, which allows fowls some discretion in 

 choosing an open-air temperature. This is particularly advisable in 

 poultry houses in which attention cannot be given except in the morning 

 and the evening. 



