There are, indeed, no known means of determining beforehand the sex of fowl; except, perhaps, that cocks may be more likely to issue from large eggs, and hens from small ones. As, however, the egg of each hen may be recognized, the means are accessible of propagating from those parents whose race it is judged most desirable to continue.
INCUBATION.
The hen manifests the desire of incubation in a manner different from that of any other known bird. Nature having been sufficiently tasked in one direction, she becomes feverish, and loses flesh; her comb is livid; her eyes are dull; she bristles her feathers to intimidate an imaginary enemy; and, as if her chickens were already around her, utters the maternal “cluck.”
When the determination to sit becomes fixed—it is not necessary to immediately gratify the first faint inclinations—the nest which she has selected should be well cleaned, and filled with fresh straw. The number of eggs to be allowed will depend upon the season, and upon the size of egg and hen. The wisest plan is not to be too greedy; the number of chickens hatched is often in inverse proportion to the number of eggs set—five have only been obtained from sixteen. An odd number is, however, to be preferred, as being better adapted to covering in the nest. Hens will, in general, well cover from eleven to thirteen eggs laid by themselves. A bantam may be trusted with about half a dozen eggs of a large breed, such as the Spanish. A hen of the largest size as a Dorking, will successfully hatch, at the most, five goose-eggs.
When hens are determined to sit at seasons of the year at which there is little chance of bringing up chickens, the eggs of ducks or geese may be furnished her; the young may be reared, with a little painstaking, at any time of the year. The autumnal laying of the China and of the common goose is very valuable for this purpose. Turkey-hens frequently have this fit of unseasonable incubation.
Where, however, it is inconvenient to gratify the desire, one or two doses of jalap will often entirely remove it; and fowls often lay in three weeks afterward. Some place the would-be sitter in an aviary, for four or five days at most, and feed her but sparingly; from the commencement of her confinement, she will gradually leave off clucking, and when this has ceased, she may be again set free, without manifesting the least desire to take to the nest again, and in a short time the hen will commence laying with renewed vigor. The barbarous measures sometimes resorted to should be frowned upon by every person with humane feelings.
Three weeks is the period of incubation; though chickens are sometimes excluded on the eighteenth day. When the hen does not sit close for the first day or two, or in early spring, it will occasionally be some hours longer; when the hen is assiduous, and the weather hot, the time will be a trifle shorter. Chickens have been known to come out as late as the twenty-seventh day.
It may not be uninteresting to note the changes which the egg passes through in hatching. In twelve hours, traces of the head and body of the chicken may be discerned; at the end of the second day, it assumes the form of a horse-shoe, but no red blood as yet is seen; at the fiftieth hour, two vesicles of blood, the rudiments of the heart, may be distinguished, one resembling a noose folded down on itself, and pulsating distinctly; at the end of seventy hours, the wings may be seen, and, in the head, the brain and the bill, in the form of bubbles; toward the end of the fourth day, the heart is more completely formed; and on the fifth day, the liver is discernible; at the end of one hundred and thirty hours, the first voluntary motions may be observed; in seven hours more, the lungs and stomach appear; and, in four hours after this, the intestines, the loins, and the upper jaw. At the end of the one hundred and forty-fourth hour, two drops of blood are observable in the heart, which is also further developed; and, on the seventh day, the brain exhibits some consistence. At the one hundred and ninetieth hour, the bill opens, and the muscular flesh appears on the breast; in four hours more, the breast bone is seen; and, in six hours afterward, the ribs may be observed forming from the back. At the expiration of two hundred and thirty-six hours, the bill assumes a green color, and, if the chicken be taken out of the egg, it will visibly move. At two hundred and sixty-four hours, the eyes appear; at two hundred and eighty-eight hours, the ribs are perfect; and at three hundred and thirty-one hours, the spleen approaches near to the stomach, and the lungs to the chest; at the end of three hundred and fifty-five hours, the bill frequently opens and shuts. At the end of the eighteenth day, the first cry of the chicken is heard; and it gradually acquires more strength, till it is enabled to release itself from confinement.
After the hen has set a week, the fertility of the eggs may be satisfactorily ascertained by taking a thin board with a small orifice in it, placing a candle at the back, and holding up each egg to the points of light. The barren eggs may then be removed, and used, hard-boiled, for young chickens. Some reserve this for the eleventh or twelfth day.