Foods and Their Adulteration / Origin, Manufacture, and Composition of Food Products; Description of Common Adulterations, Food Standards, and National Food Laws and Regulations

by Harvey Washington Wiley

—The introduction of the incubator for the hatching of eggs with the other necessary arrangements for the caring for young chicks has perhaps done more than any other one thing to revolutionize the method of preparing poultry for the market. By the use of the incubator the hatching of chicks is regulated with the utmost degree of nicety. A larger percentage of eggs produce chicks and the expense of the incubating process is greatly diminished. The incubator is in its widest significance a thermostat in which the eggs may be placed and maintained constantly at the temperature of the hen’s body, namely, about 102 degrees F. The arrangement of the chicken house and the other environments of the young chick are shown in [Fig. 12].

Care of Young Chicks.

—The principal points in the care of young chicks are fresh air, freedom from infection by epidemic or contagious diseases, exclusion of insect pests, even high temperature, and abundance of food. The young chick is especially sensitive to low temperatures and must be protected from cold, especially from cold rains. For this reason the chicks, after hatching, must be kept, if it is not summer time, in a room where the temperature can be regulated until they have acquired some degree of strength and vitality. The temperature of the chicken house for the young birds should not be lower than 85 or 90 degrees F.

A temperature of about 102 degrees F. is found very favorable to the development of the chicks in the eggs, although the temperature may sometimes fall to 101 or rise to 103 degrees F. without materially affecting the results. Experiments show that too low a temperature arrests the development of the chick. On the contrary there seems to be no indication that an increase of heat, up to 103 degrees F., has any tendency to kill the chick in the last stages of development. It is found best in all cases to set the eggs in the incubator as soon after they are laid as possible. Where the age of the egg is not known it should be carefully candled, that is, held up between the eye and a light in order to determine its condition. In old eggs, the yolk, on candling, becomes more or less diffused with the white and such eggs are to be rejected for incubator purposes as they are not likely to produce chickens. The fertility of the egg must also be assured before placing in the incubator. An unfertilized egg is so much loss in the incubator since it might have been used for food purposes, since the egg, for marketable purposes, when fresh is just as good as a fertilized egg. It is an observed fact that the complete fertilization of the egg, that is, the proper union of the male and female germ cells, is not always complete at the time the egg is laid, but the mingling of the two elements takes place under proper conditions afterwards. The development will also depend upon the vitality of the germ and its component parts. Just, for instance, as the color of the feathers, the size of the body and the general character of the chick may be inherited from either parent, so the vital qualities are much more strongly shown in some eggs than in others. The proper germination of the egg may also be improved by many of the conditions of environment. In the case of eggs, any slight change which would interfere with the functions of the yolk or albumin, both of which are extremely sensitive to change, would interfere with the growth of the embryo either by depriving it of food or subjecting it to other conditions in which its vitality would be diminished or destroyed. The fertilized egg may be separated from the non-fertilized also by candling. At the Rhode Island station it is found that a very good light for candling is the ordinary calcium carbide bicycle lamp, placed in a proper candling box. This is a strong white light quite equal in power to the electric incandescent light and is not so trying to the eyes.

When eggs which have been submitted to incubation permit light to shine through and show the yolk suspended in the upper half of the center as a clearly defined mass, which quickly reassumes its position in turning the egg with its long axis nearly horizontal, they are probably infertile or sterile. When, on the contrary, the yolk assumes indefinite outlines, approaching near the upper portion of the shell at the large end or appears with a thick spur upon its upper side, it may be regarded as having started to incubate. In the later stages the embryo can be plainly seen, because it becomes opaque and cuts off more of the light. In the incubation of eggs the candling is resorted to during the first few days of the experiment in order that the unfertilized eggs may be separated. The best time for the candling, if it is practiced only once, is on the sixth or seventh day of incubation. By that time all the eggs which are fertilized will be so changed as to be easily recognized by the candling process. Experience has shown that eggs which are more than two weeks old are not profitable for use in incubators since the percentage that does not hatch is so large. The incubating part of the plant is sometimes placed in the cellar over which the brooding house is built.

The brooding of young chicks is of the utmost significance. In Europe the changes in temperature are much less violent than in this country. The principal brooding houses in the United States are in the North where the temperature often falls in winter to below zero while in the summer it may rise to blood heat, a difference of over 100 degrees F. For this reason the incubating houses in the United States are often placed in cellars where the uniform conditions of temperature are more easily secured. There is no objection to this location provided proper care be taken to secure ventilation and the proper content of moisture in the atmosphere. In Great Britain the incubating houses are usually placed above ground instead of in cellars. The mean range of temperature in an incubating room in Great Britain, from March 12, 1903, to March 30, 1904, was 10 degrees. The highest temperature registered was 70 degrees on the 24th of June and the lowest 42 degrees in January. The humidity of the air was also quite constant, the lowest degree of humidity being 59 and the highest 94. These data show a very even temperature in the room itself. Of course the temperature in the incubator is necessarily greater, being that already referred to, namely 102 degrees.

Early Market.

—One principal object in the raising of chicks is to force them to an early maturity in so far as size and palatability are concerned. The sooner the young broilers can be made ready for the market the more economy there is in their production. To this end they ought to receive a more abundant and specially prepared kind of food than if they were intended for ordinary farm purposes. In other words, the forcing process should be pushed as far as possible without interfering with the health and normal functions of the bird. Foods which are nutritious and stimulating and promote vigorous growth should be employed. Birds prepared in this way for the market are extremely tender and palatable and bring the highest prices where their merits are recognized.

Artificial Feeding.

—Where chickens of greater age are prepared for the market they are subjected, during the last two or three weeks previous to sale, to a forcing process in order to produce more fat and make their flesh more palatable. To this end the chickens are fed from time to time mechanically by passing a tube into the craw and forcing the food therein. Fowls prepared in this way bring high prices in the market and the largest profits to the growers. It is a method, however, which is not used in the raising of the ordinary poultry found on the market.