POULTRY ON THE GENERAL FARM 
steel, are best. Wafers filled with ether or similar liquid are 
more sensitive but weaker in action. Hard-rubber bars are 
frequently used. 
The most practical system of controlling evaporation is a 
system of forced ventilation, in which the air is heated 
around the lamp-flue and passes through the egg-chamber 
at a rate determined by ventilators in the bottom of the 
machine. With the outside air cold and dry only slight cur- 
rent is required, but as the outer air becomes warmer or 
damper more circulation is needed. 
Turning the egg is not the work that many imagine it to 
be. It is not necessary that the egg be turned with absolute 
precision and regularity. An elaborate device for this work 
is useless. The trays will need frequently to be removed and 
turned around or shifted, and the eggs can be turned at this 
time by lifting out a few on one side of the tray and rolling 
the others over. 
Two other points to be considered in the incubator are: A 
suitable nursery or place for the newly hatched chick, and a 
good thermometer. 
Rearing Chicks. 
If it is very early in the spring, and the ground is damp, 
it is best to put the hen and her brood in some building. 
During the most of the season the best thing is an outdoor 
coop. The first consideration in making a chicken-coop is 
to see that it is rain-proof and rat-tight. The next thing to 
look for is that the coop is not air-tight. Let the front be 
of rat-tight netting or heavy screen. The same general plan 
may be used for small coops for hens, or for larger coops to 
be used as colony-houses for growing chickens. The essen- 
tials are: A movable floor raised on cleats, a sliding front 
covered with rat-tight netting, and a hood over the front 
to keep the rain from beating in. If used late in the fall or 
early in the spring a piece of cloth should be tacked on the 
sliding front. 
The chicken-coops should not be bunched up, but scattered 
out over as much ground as is convenient. Neither should 
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