On the seventh and the fourteenth day, it is a good plan to test the eggs in the incubator, so that the infertile eggs may be removed. This is done by a process known as candling. Hold each egg up in front of a light and note the appearance of the interior of the egg. This can be done by making a hole in a box, that will fit over a light or lamp, and then holding the eggs up to the light, showing through the hole, which should be in line with the flame. If the egg appears clear, free from any dark spots, then the egg can be taken out of the incubator, as it is not fertile, and will not hatch. However, if the egg shows a dark spot, about the size of a bean, and you can detect small blood vessels running from it, then you may be assured that the egg is coming along in good shape, and will hatch out in due time. With these points well in mind, one will have little difficulty in properly running an incubator, providing he has a reliable machine to begin with. Of the matters considered in this chapter, probably the most important factor of all is the constant maintenance of a uniform temperature. Now, then, let us consider that the chicks are pipping the shells and are ready to start out in life. We will therefore consider the care of the chicks in the next chapter, until they are able to care for themselves. CHAPTER V. BROODING Whether we hatched the eggs by means of an incubator, or bought the day-old chicks, if we have no mother hen to care for the chicks after they are hatched, we must take care of them ourselves. This is called the brooding period. Unless the hatch is quite late, which, by the way, is not desirable, we will have to arrange to supply some cheap, simple form of artificial heat, to prevent the young chickens from getting chilled. This is accomplished in several different ways, but we will only discuss the more common ways here. There are several different makes of readymade brooders on the market, but one can in a few hours spare time, construct a brooder that will answer the purpose. The chief part of the brooder is the source of heat. Usually these heaters can be bought for a few dollars, and placed in a good box supplied with a little litter on the bottom.