INCUBATION 



19 



to the great detriment of the other chicks. The temperature 

 of 'the machine at the time of hatching is very difficult to 

 regulate, and this is due to the amount of heat generated by 

 the chicks at that critical moment. The rise of temperature 

 may not injure the chicks that are already hatched, but may 

 greatly injure the heavier breeds which have not as yet 

 broken the shell. 



The eggs should be clean. Dirt or grease on an egg 

 ■ prevents the free circulation of air and may be the cause of 

 death by suffocation of the delicate life germ or embryo in 

 the egg. 



Running the Machines 



There are no infallible rules for the running of an in- 

 cubator. The amount of moisture and ventilation required, 

 the manner of turning the eggs and cooling, and the many 

 details of the operation cannot be indicated in a definite and 

 decisive manner for every machine, and are subject to varia- 

 tion according to the make, the system of the machine, and 

 the external conditions under which we are working. 



I give here only a few very general rules to be observed. 

 The manufacturer sends with the machines the necessary 

 instructions. Different machines differ in important essen- 

 tials, but the breeder will have to discover by practical ex- 

 perience many details of the operation which the manu- 

 facturer cannot supply and which differ according to the 

 outward circumstances and the individual conditions in 

 which one may be placed. 



The temperature is a matter of utmost importance, as 

 it forms the essence itself of incubation. As the embryo or 

 life germ is brought to actual life through the agency of heat, 

 it will be seen readily how very important it is that the tem- 

 perature should receive our most careful attention. I think 

 the temperature should be kept as near as possible at 103 

 degrees Fahrenheit. One should be, careful about the ther- 

 mometer being correct before placing the eggs in the machine. 

 It occasionally happens that there is some little defect and 

 considerable trouble is caused. 



The embryo chicks generate animal heat as soon as they 

 comjnence to make growth and the volume of heat increases 



steadily toward the latter part of the hatch. This is the 

 reason why it is usually necessary to re-adjust the regulator 

 during the last week or ten days of the hatch. 



The amateur breeder who is using an incubator for the 

 first time will naturally be tempted to look too often into the 

 interior of the machine' in order to see how things are pro- 

 gressing. It is very imprudent to open the door of the in- 

 cubator often. Keep the door closed as much as possible 

 and you will find it to your great advantage. This applies 

 specially to the time of actual hatching. If your neighbor 

 or friend wishes to see how things work tell him to come 

 round some other time when there are no eggs in th^ machine, 

 and then examine it as much as he may desire. Offer to 

 give him all the verbal explanation he may wish, but do not 

 risk losing a hatch to oblige him by actually showing him 

 the interior arrangement while eggs are being hatched. 



Generally it is best not to open the egg chamber after 

 the chicks begin to break the shell until the hatch is quite 

 finished. A chick that is not strong enough to make its way 

 out of the shell is generally not worth helping, while frequent 

 opening of the doors may result in the complete loss of a 

 valuable hatch of eggs. 



There may be times when it is absolutely necessary to 

 open the machine, even while the chicks are hatching. A 

 chick may have hatched but may be caught in an unnatural 

 position by the empty shells, or partly smothered by these 

 shells, but if it is necessary that the incubator should be 

 opened, special attention should be given that no drafts or 

 currents of cold or foul air enter the machine from the out- 

 side and the door should be kept open just long enough to 

 perform the necessary operation. 



If the eggs are fresh laid and of strong vitality, and the 

 incubator properly attended to, the chicks should begin to 

 break the shells on the twentieth day and the hatch should 

 be completed the twenty-first day. , 



Chicks that hatch out too early or too late and specially 

 the latter, are always weak and should they happen to sur- 

 vive the first stage of life, they seldom develop properly and 

 very rarely grow into fine or normally developed bifds. 



VIEW OF TOLMAN FRESH-AIR INCUBATOR CELLAR 

 There are foiir ventilating shafts, which can be seen in the photograph, extending to within a foot of the cellar floor. These are 12 inches 

 square and are always open. The radiator shown in ground plan, (see page 18) is to remove the impure air from the center. Seven-inch tiling is run 

 from this radiator to each corner of the cellar, about 4 inches under the floor, carrying the impure air directly out of the building. The two large win- 

 dows in the south side and the transom windows over the door allow plenty of fresh air to enter. 



