Hatching the Eggs.
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.
