Part 7

The next thing is testing the eggs. This matter is essential as well as economical, with both hens and incubators. I once knew a man who ran a six hundred-egg machine for three weeks on one fertile egg. The other 599 proved infertile, and he did not know it until they refused to hatch at the end of three weeks--a great waste of oil, but a greater waste of time,--three whole weeks in the best part of the season. Another man kept forty hens sitting three weeks with an average of one fertile egg to each bird, when three of them could have done all the hatching just as well, and then, at the end of four days, could have had the rest put upon better eggs.

A great waste of hen power, you will say, with time lost, together with forty dozen eggs, which would have been just as good for table use had they been tested out in four days. It often happens in the winter, when eggs are apt to be infertile, that, after testing the contents of four trays, they can be contained in three, when the other can be filled with fresh eggs. Here is where the advantage of adjustable trays comes in. Often the operator running a large machine has not eggs enough to fill it without a part of the eggs becoming very old, and also losing ten or twelve days of valuable time; with the adjustable tray, eggs can be introduced at any time, and the same heat preserved on all. I usually test duck eggs at the end of the third day. The fertile germ is then plainly visible, and the eggs can be passed before the light, several at a time.

The novice had better postpone the operation till the fourth day, when he, too, will have no trouble in detecting the germ. The same rule will hold good with all white eggs, but dark-brown eggs should not be tested till the sixth or seventh day. This can be done much sooner, but a large machine full cannot be tested in a minute, and the eggs should be far enough advanced so that the operator can take two or three in his hand at once, and passing them before the flame, readily detect the germ. I never use a tester for duck eggs, as a simple flame is sufficient, the egg being translucent.

During the first stages of incubation the germ is very distinct, even at the third day. The clear eggs are reserved for family use or disposed of to bakers. An expert cannot distinguish them from a fresh-laid egg, either in taste or appearance. There is usually a small percentage of the eggs that are slightly fertilized, in which the germ will die during the second or third day. These can be readily detected at the end of the fifth day, and should be taken from the machine, and reserved as food for the young ducklings. Another and potent reason why all infertile eggs, and those with dead chicks in them, should be taken out of the machine, is that after the circulation begins in the egg, especially during the last part of the hatch, the temperature of a live egg is several degrees higher than that of a dead one. The one radiates heat, the other absorbs it; so that if the operator is running his machine 102 degrees, with his glass on a dead egg, he may be all unconsciously running it at 104 or 105 degrees on a live one.

I had a letter from a man some time ago stating that his thermometers were developing strange freaks,--that though they registered the same while in water, at 103 degrees, when lying on the eggs a few inches from each other in the machine, they were several degrees apart, and wishing to know by which he should run, the higher or lower. I wrote him that his glasses were all right, and that he was the one at fault, and had he followed instructions and tested his eggs he would have had no such trouble. He wrote that as his machine was not quite full, and as he had plenty of room, he neglected to test them, thinking it would make no difference.

I do not propose here to give my experience, together with the many experiments made during the last twenty years, but shall aim to give the reader simple instructions for hatching and growing ducks for market and selection of breeding stock. I would say here that the first thing for the operator to learn in turning the eggs is to do it carefully and well, without breaking or unnecessarily jarring them; and then, to do it as quickly as possible, especially if done in a cold atmosphere, so as not to derange the heat in the egg-chamber. The next thing is to maintain as even a temperature as possible during the hatch. I do not think that a variation of one degree is at all detrimental. But different people have different ideas of regularity. A man who did not have a first-class hatch, wrote me that he had kept the machine right to business, as it had run between 90 and 110 degrees during the entire hatch. Another man wrote that his machine had been as low as 100 degrees, and once up to 103 degrees, and wishing to know if I thought it would be fatal to his hatch.

There is no such thing as accuracy in the composition of some men, things are run "hap-hazard," failure and misfortune are always attributed to conditions, circumstances, or hard luck,--never to themselves,--and in case of a poor hatch, always the incubator. Instructions go for nothing with them. An enterprising incubator maker told me one day that he believed that the world was composed of cranks and fools (at least the poultry part of it). The one-half did not know anything, while the other half had all that was worth knowing and despised all instructions and common-sense.

In running your machine, the first step is to set it level and see that the glasses register alike in both ends of the machine. Next, procure good oil, 150 test (as poor oil will necessitate frequent trimming, besides crusting the wick). Do not use more flame than is necessary, as it will only be a waste of oil, and with some machines will increase the ventilation, and at the same time decrease the moisture. Be regular in both filling lamps and trimming them, as irregularity frequently involves forgetfulness, and that sometimes means disaster to the hatch. In trimming, it is well to turn on the same amount of flame in relighting your lamp as it had previously.

In the Monarch Incubator this required amount can readily be seen at once by the action of the regulating bar. It informs the operator just when he has enough,--when too much and when too little. Keep both lamps and chimneys clean, and have stated periods for turning your eggs, which should be done twice each day. As I said before, an egg-tester is not required with duck eggs, as they are so transparent that the whole process can be plainly seen without in the flame of a common kerosene lamp. If a duck egg is carefully examined, after being subjected to a heat of 102 degrees for twenty-four hours, a small dark spot will be seen about the size of a large pin-head. This little spot, if the egg is gradually turned, will always float over the upper surface of the egg. This is the life germ, and the first indication of fertility in the egg, and is represented in Figure 1.

At the end of forty-eight hours this dark spot will have nearly doubled its size, and a faint haze will appear around its edges a shade darker than the surrounding contents of the egg. This haze is the first appearance of the blood veins radiating out from the germ.

Figure 2 shows how the egg appears at this stage with the air-cell slightly enlarged.

At the end of the third day the dark spot, which is the heart of the embryo duck, can still be seen; but not so distinctly, because a dark circle some three-quarters of an inch in diameter will now appear in the upper surface of the egg, in the centre of which the dark spot is visible. This circle is several shades darker than the rest of the egg, and no matter how the egg is turned will always float in its upper surface.

Figure 3 represents the egg at this stage, with its enlarged air-cell.

Figure 4 represents the egg as it appears at the end of the fourth day. The circle surrounding and inclosing the germ will have nearly doubled in size, and is of a still darker hue; indeed, the whole contents of the egg is perceptibly darkened. If the egg is broken carefully at this date a delicate tracery of veins will be found to have enveloped the entire yolk of the egg, all originating from the centre or heart of the embryo; the pulsations of which (if the shell is removed) can now be plainly seen with the naked eye. This net work of veins cannot be plainly seen with a common lamp, but with a powerful glass are very distinct. This latter is not at all necessary in testing the egg.

The discovery and locations of the minute organisms may be interesting to the scientist, but not at all necessary to the operator, who simply wants to be assured of the life and health of the germ. This he can readily determine from the increased size and gradual development of the circle; it, and the contents of the egg, now assume a darker shade. Up to this time I use no moisture, and the contents of the eggs have gradually evaporated and the air-cell proportionately enlarged. This air-cell is slightly enlarged till the tenth day, when no further evaporation should take place. About three days before hatching the rapidly developing duck will gradually diminish the size of the air-cell, leaving himself just room enough to work out.

Nature, in the case of the old hen, provides for her own contingencies, while we must resort to art to obtain the same conditions.

While incubating under the hen during the first few days, the egg evaporates rapidly. Then the pores gradually become coated with an oily secretion from the feathers of the hen until evaporation ceases. Now, we cannot successfully fill the pores of the eggs, it is too delicate an operation to attempt; but we can easily obtain the same conditions in another way, and that is to prevent the further evaporation of the egg by vaporizing water in the egg-chamber, so that evaporation will not take place. Exactly when this should be done is already known, but exactly how much is quite another thing, and depends largely upon the conditions of the atmosphere outside. The point is this: the humidity inside the egg-chamber must be the same, whatever the conditions are outside.

If your machine is in a warm, dry room, heated by a fire, far more evaporating surface will be required than in a cool, dry cellar, for the reason that water vaporizes just in proportion to its heat; and as the circulating pipes upon which the water-pans rest must necessarily be much warmer in a cold room than in a warm one, of course more surface must be exposed in a warm than in a cold one. The operator will always have to use his judgment more or less in that. It may perplex the novice somewhat, but it is easily understood when one becomes accustomed to it.

As a rule, in our machines, we introduce one moisture pan about the 18th day for both duck's and hen's eggs. It makes some difference whether a machine is run in a humid atmosphere near the seashore or in a dry, rarified atmosphere at an altitude in the country.

Figure 5 represents the egg at the end of the fifth day, the circle enlarged, shaded darker in color; the whole egg being slightly darker in hue.

Figure 6, at the end of the sixth day, shows still more plainly the germ undergoing a gradual change in the egg, enlarging and assuming a darker hue. The outline of the circle is now gradually acquiring the form of an ellipse, and in a live embryo the line of demarkation should be distinct. If it is at all wavy and irregular in its outline, and instead, remaining intact, the contents of this ellipse show a disposition to assimilate with the surrounding liquids when the egg is revolved, it can be safely removed as a dead duck.

Figure 7 represents a dead embryo, as it will appear from the seventh to the twelfth day. The germ being separated and appearing in dark irregular blotches over the entire surface of the egg; the egg having become nearly opaque over its entire surface. At this stage the egg, if it has not already become so, will soon be very offensive. These should be removed at once and handled carefully the while, as they are apt to explode and unpleasant consequences ensue. The operator should run no risks, as discoloration on the outside shell of a duck egg is a sure sign of decay, and they can safely be taken from the machine. There are always a certain number of duck eggs (especially during the month of August and the latter part of July) that have the appearance of fertility during the first three or four days of the hatch, but do not possess vitality enough to carry them through. These die at all stages of the hatch; neither operator nor machine is responsible for them. This is caused by the condition of the mother bird.

In order to economize the room thus made by the removal of the fertile eggs, I run a small 150-egg machine, in connection with twenty-one of the largest size, using it, as it were, as a tender. When filling one of the larger machines, I always fill one tray in the smaller one so that when the eggs in the large one are tested, after the third day, there will usually be eggs enough in the small tray to replace those removed as infertile, so that the large machines are kept full during the entire hatch by the little one. Thus the small machine is made to accomplish far more than it would were it run through the hatch. I am thus enabled to have a hatch come off nearly every day, consequently our eggs are never older than that when introduced into the machine. Always date each day's quota of eggs--keep them by themselves, then there will be no mistakes made. I have known parties to keep one general receptacle for their eggs, and when filling their machine take them from the top, while the bottom ones were never disturbed, not even turned, and of course soon became worthless for any purpose.

Figure 8 denotes the appearance of the egg during the eighth day of incubation. If portions of the shell are carefully removed at this stage, the rudimentary intestines may be plainly seen, together with the gradual development of the beak and eyes, as well as the trembling of the pulsating arteries through the whole embryo.

At this stage the operator should mark all doubtful eggs and return them to the machine, as he will find plenty of room there. He will soon become expert, and can detect life and death in the germ at a glance. Experience alone will give the operator an insight into this business. The incipient stages of decay, though easily detected by the expert, cannot be intelligently described by him. The application of a little heat for the short space of twenty days to an inert mass, developing it into active, intelligent life, is simply wonderful. The process and effect he can easily describe, but the procreative power behind it all is beyond his ken. Should a little duckling be taken from the shell on the thirteenth or fourteenth day it will resemble Figure 9. It will kick and struggle several moments after its removal. The yolk is not yet absorbed, but the process is just beginning and will continue until the twenty-fourth day, when it will be nearly absorbed. The egg, from the fourteenth day rapidly assumes a darker hue.

The extremities of the little bird gradually develop, the feathers grow, and at the twentieth day the egg is opaque. At this stage the embryo will endure greater extremes of heat or cold than at the earlier stage of the hatch. I should not advise the operator to presume upon this, however, but just make the conditions as favorable as he can, so that the little bird will have the strength to free himself from the shell. I need not say that this is the most critical time during the whole process, and matters should be made as favorable for the little duckling as possible. About the twenty-fourth day he will be already to break the shell, but, unlike the chick, who will make his way out of the shell a few hours after he has pipped, the duckling will lay for forty-eight hours before he is ready to come out. At this time there should be plenty of moisture in the egg-chamber, for should the orifice or broken parts become dry, and the little duckling, in consequence, be attached to the inside lining so that he cannot turn, he can never get out without help.

When the hatch is well underway a little more air should be allowed to circulate in the egg-chamber, and a part of the evaporating surface can be removed, for as each duckling makes its appearance he becomes a little sponge, until dried off, and furnishes plenty of moisture for the machine. When nearly dried off the duckling should be dropped into the nursery below the egg-trays. While hatching, the eggs should be kept pipped side up in the trays, as the birds sometimes get smothered when the orifice is underneath. The dry birds should be dropped below about once in four hours, for, if allowed to accumulate, they will roll the egg upside down, crowd the egg-shells over the pipped eggs, or pile themselves over the egg, smothering the young birds.

This work should be done very quickly, so as not to derange the temperature of the machine. Be sure to keep the heat up in your machine, for its tendency is always to go down during hatching, for the reason that the egg radiates a great deal of heat, while the little duckling, with its woolly covering (which is a non-conductor), retains it. Many people advocate allowing the little fledglings to remain with the eggs until all are hatched, but this is all wrong, not only for the above reasons, but for one which is far more important than either.