A.tifICIAL INCUBATION.

New Zealand Mail, Issue 1751, 27 September 1905, Page 62

ARTIFICIAL INCUBATION.

(By W. H. Tombs, in the “Australian Hon.”) Since the time of the Egyptians, who hatched chicks by artificial methods, farther back than history can trace, the ©gg has been subjected to the tender* mercies of all kinds of invention by man, including incubator rooms, cellars, ovens, and many and various makes and shapes in incubators with more or less success. Now the recent competitions show us we have to-day the 200 egg hen. This is not what the Egyptians had. as in their time, we believe, hens usually laid their eggs in clutches or batches of 15 to 25, two> or three times a year according to the constitution „oi* strain of the hens. So the hen of today is an abnormal creation, for there is little doubt the hen was originally intended to lay a clutch of eggs and then incubate them. But man, never satisfied, wanted more eggs, and has been breeding for the last 50 years and over, to produce the hen that will lay the greatest amount of eggs in the short period of two or three years, and then, too, the demand for eggs has been so great, that it would be impossible to raise all the fowls required to lay them now, without the aid of incubators. Thus, with poultry farmers, the incubator is as much a necessity, for him., as the separator is to the dairy farmer, for he can get chicks at any time, and thus have pullets laying all the year round. And so we now have millions of chicks raised annually with incubators and brooders, and as we want our hens to lay well in the winter time, we must get our olxicks hatched out early, as it is the hen that lays early in the winter that pays us well, and to get these we must have incubators, as the hens will not, as a rule, go broody until the warm weather comes, wnen it is toe late to think of early chicks. Even a breeder who has only a small flock of birds should have an incubator. Why should half his hens waste their time in hatching ohicks, when they should be laying with eggs at Is 6d to 2s per dozen. Half a dozen broody hens, hatching 50 chick®, and wasting their could by laying during that, period, more than pay for an incubator, which is far less trouble than managing six broody hens. The sooner people awake to the fact that incubators are not a luxury, but a necessity, the sooner the poultry industry here will become the most important of all our natural resources. See how it is in America, more dollars out of poultry, than out of both grain and gold together. Some people are of the opinion that incubator batched chicks and stock are not so strong as those hatched and raised by hens. This is a fallacy, as most of the winning stock at all leading English and American shows, have been artificially hatched and raised for generations, and have never heard the cluck of the mother hen. An incubator is, as far as I know, the only thing that brings forth life artificially, and to obtain the best results, in making and working our incubators, we must follow as closely as possible the methods of the natural incubator, the hen. I do not intend to dwell much on the making of incubators, as I consider there are plenty of good machines on the market., of various styles and ■makes, but nearly all made to follow as near as possible the methods of the hen, and all aiming for the one end—to hatch out the ohicks successfully. I may as well say here, whatever make of machine you get, follow the maker’s instructions olosely, as he should know best how his particular machine should be used. Having selected your machine, which, to be classed as a good one, must have a double walled case, or the inner walls must be packed or lined with felt or building paper. The dead air space

should be small, and the air completely entrapped, in order that the egg chamber may not be greatly effected by the outside atmospheric changes, as a mar chine that leaks air, cannot well be kept at a uniform temperature, nor can it be properly ventilated with accuracy. Some machines are more substantially built, some have better regulators, some better principals of ventilation, some more easily operated than others, but with little care, almost any machine can be made to hatch a fair percentage of fertile eggs. What I consider the best place to run the machine in, is a wellventilated cellar, failing this, a well built room where the temperature cannot be easily affected 'by outside atmospheric changes. The next best place will be that which is handiest. Now we want fertile eggs, and to obtain these, we must beg n wbh the hen that has to lay them. To get. them we must have our hens well fed: well fed does not mean fat hens, but birds that are properly fed on a well-balanced ration and they must be healthy and vigorous. Having the fertile eggs, we want the necessary conditions required to hatch them. These are heat, moisture and ventilation, and the nearer we can imitate the hen in supply iffffc'these requirements, the surer we are of success. The hen, if left to herself, will prepare a nest in as small a spjaco as' possible, so as to be able to well cover her eggs, as the body has to supply the heat to hatch them. She sits on them for 21 days and from time to time moves them about in her nest, turning and changing them in position, so as to give them all about the same amount of heat in turn. She covers the eggs with her feathers, which act as regulators to the outside air, and thus retain the required moisture in the eggs during the hatching process; the feathers allow a free circulation of air through their millions of pores, yet they never allow a current of air to pass trirough them, and so. they prevent a too rapid evaporation of the mcisture contained in the eggs.

An egg contains about 75 nor cent, of water, which is sufficient, when hatched under natural conditions, and is also sufficient under artificial conditions, if it is properly retained. It matters little whether the hen is sitting in a moist place on the ground, surrounded by a moist atmosphere, or in a hayloft, or on the top of an hayrick, surrounded by dry air, as she brings out- just as large a hatch in one place as the other ; so it will be seen that changes in the humidity of the atmosphere, have no serious effect on the incubation of an egg, for in the hens nest the eggs are surrounded by feathers which retain the moisture from the eggs in her nest and exclude it in the surrounding atmosphere, should there be an excess. For in natural incubation a spontaneous diffusion of the gasses takes place through the feathers, while they retain the heat and assist in rotting the'shell. In artificial incubation it is always an easy matter to get the required heat, but the main trouble is in giving the eggs the correct amount of ventilation without causing a draught or current of air. Although a free circulation and interchange of air is necessary, yet a strong current of air is undesirable, as a too rapid circulation would take away the moisture too fast. But. now, in most of the latest machines, the question of ventilation and moisture have been nearly solved, or to such a degree, that with a little experience and common-sense they can be operated with success. This moisture question has been “hashed up” and “chewed over” as it were many times; some claimed to have solved the problem, but fail to explain how; some say none is required, another manufactures it, and so on. But I maintain that ventilation and moisture are so closely connected that they Bhculd not he separated in an incubator, for just a certain amount of ventilation will be required to carry off the carbonic acid g.as, thrown off by the eggs, or many of the chicks would be killed in the shell from the 14th day onward by the accumulation of the gas in the egg chamber. Now we will proceed to run the machine. Just get a good brand of oil, and fill the lamp within half an inch. The wick must be well trimmed so as to burn without “tails,” just rounding the corners of the wick prevents this. In trimming the wick, which is best done twice daily (as I notice if the flame is extinguished and the lamp cooled the flame burns much steadier and brighter), use the back of an old knife or some similar blunt instrument, and rub the charred wick off, then light and turn up so as not to smoke. *The oil font should be ventilated so. as to prevent the accumulation of gases, which sometimes cause the lamps to fire. Any damper regulated machine can be greatly assisted by turning the flame up or down in hot or cold weather as the case may be. As the diamper can only raise sufficiently to let off the heat that will pass out of the flue, if more be generated by the lamp than can pass out, and the temperature in the machine shows a tendency to rise, it is evident that the flame is too high. Wh en lie damper closes and the machine does not warm up to the proper temperature in a reasonable time it is evident that the lamp is not generating, enough heat, and the flame should be increased. With the slip or sleeve regulator, a device with which the capsule operates a rod, which raises or lowers a case

amound the lamp wick, increasing or decreasing the flame while the wick remains the same, there is direct regulation and a saving in fuel, but it ha* the disadvantage of being slow, and ia order to be effective, the burner must be kept perfectly olean, and this necessitates cleaning the lamp twice daily, for if the wick or tube becomes ever so slightly encrusted, the slip or sleeve is very apt not to work. Having started the lamp, the next thing is to get the correct heat., an to do this we must study the regui. x -; the best time to start the machine is in the morning, then you will have all day to watch the progress of the thermometer. Lay the bulb of thermometer on the bottom of an egg tray , and heat up to 100 deg., or if bulb of thermomentor is raised about Ik inches from bottom of egg tray run to 102 deg., and see that the regulator raises at this, so as to prevent the machine getting any hotter. Have the machine running like this for two days, then put in the eggs. When you havo properly adjusted the regulator the eggs will take about- 30 hours to warm through. The mercury should register 1024 deg., for first three days, after that the macliin-e will get steady, and then raise heat to 103 deg., and keep it at that right through the hatch. After the 12th day a little less flame will be required, as the eggs will then generate a little heat themselves. The eggs will not require to be touched for the first two days, nor shall the machine be opened, as this is a critical period, the starting of the gerrn, and very little will kill it at this stage. On the morning of the 3rd day the eggs should be turned; turn slowly, and that will be sufficient cooling for the eggs at this stage and until after the first- test (7th day). Then the turning process should occupy 10 minutes. Test again on 14th day and then turn and cool for 15 minutes if the room be a warm one; take care not to chill the eggs.__ After the first egg chips close the machine till all are hatched. Cooling the Eggs.—l have noticed, and I think it is universally so, that a successful sitter if left to herself, remains on the eggs for as much, "as three days at a time, if food and water be placed within her reach, and then only leaves the nest for a short period, and. when she returns to her nest, the eggs are quickly warme” up to their normal heat. Now we find when eggs have been removed from the incubators to be turned, and are left out some time, they are a long time regaining the normal heat again, often as long as eight hours, according to the make or construction of the machine, therefore I maintain it should only be necessary to expose the eggs whilst turning them, unless the weather be very .warm, when they could be left out a. little longer. When turning eggs they should never be placed in a draught, or exposed to the wind, or too much of the moisture will bo absorbed, and a bad hatch result.

Every time the eggs are turned they should be changed in position if postsible, as in nearly all incubators there will be a comparatively unequal temperature, I have found machines with, the tube or pipe around the machine inside, to maintain a more even temperature than those otherwise heated, but it will be noticed in most machines, that if we place a thermometer in the centre, one at the outside, and one between them, on v the tray we shall get three readings, the coolest on the outside, and the highest reading in the centre, and as it is almost impossible to make the case a perfect non-conductor of heat, we shall always have a certain amount of difficulty to contend with and hence the advisability of changing the postion of the eggs. Now, to be successful with our hatches, we must become acquainted with, the development of the air cell, as this is one of the most important guides to cooling. The air cell is the little space at the large end of the egg; which is plainly visible on the 7th day, and it must continue to grow larger every day until the 19th or 20th day, when it should occupy about one-fifth of the egg- A's unless this air cell is developed properly, by the 20th day the chick cannot turn itself in the shell, thus we find chicks, although fully developed, “Dead in Shell.” This air cell is controlled in two ways, thus, if'it developes too slow, give the egg all the air you can, not by cooling out of the machine, but by giving all the ventilation possible in the machine. If, the other hand, the air cell developes too rapidly, it can be checked by closing the ventilators as much as possible without. entirely closing them, and also by adding or supplying a little moisture to the machine, but this latter will be unnecessary except in a very hot or dry weather. It must be remembered that the air space does not increase so rapidly from the Ist to the 12th day as it does from the 13th to 18h day, so it will be seen that drying down too quickly in the-., first staves, compels us to cut off the ventilaion at the latter part which is a had practice. One should not conclude that either moisture, ventilation, or heat is the main question, but rather a proper combination of the three. There are machines that control both heat and eventilation to a satisfactory degree, but the trouble is that more air will enter a machine on a cold dav

.ffiuyn -.a/ warm one, and this is 1 where the fault lie® in self ventilating machines, •luathey do* not meet the various change® in the atmosphere. It will also be noticed that a fertile .egg gets rid of Its excess moisture, and Joses about one eighth of its weight, and about one sixth of its internal size, whilst an unfertile egg loses hardly any in size or weight. Now we will proceed to test the eggs. !A strong light will he required, and either a dark room or cellar. Test the •eggs on the 7th day (not the Sabbath) and again on the 12th day. If you are an expert you can test at the fifth day, but 'pare should be taken or you may throw away a “live” germ, jVnyway, if. in doubt, leave until the next test. IMI fertile eggs should, on the 7th day, Bhow the veins or loo>king like a spider in the egg; all those that are clear and like a hew laid, egg, are infertile and will not hatch. (These can be used for cooking or for boiling for the chicks. A number of eggs will appear to be right at the first test, but at the -second will be found to contain “dead germs” and should be rejected. The .novice will have some trouble to distinguish these, but it can soon be learnt; a good way to learn is, if in doubt, break one or two eggs. If possible test in a warm room, and care must be taken that they be not exposed too long and thus get chilled, as chilled eggs mean weak or dead chicks. There are various kinds of egg testers on the market, and most of them will be found •serviceable.

Now just a word about thermometers. 1 am of the opinion that 20 per cent, of the bad hatches are caused through bad or unreliable thermometers. I think “all glass” thermometers are the best. IA.II other conditions may be right and the thermometer bad, then the hatch is a failure. The position of the thermometer in an incubator, whether upright, inclining, or flat, or even “upside down” should not effect its action if properly made and in good working order; where hut one is used it should •be placed halfway between the centre and outside of tray, but it is better perhaps to use two for safety’s sake. The bulb of the thermometer should not rest on the eggs, for this reason, say the bulb rested on an infertile or “dead” -egg. To maintain a heat of lOSdeg on a bad egg, the heat of the chamber or drawer would have to rise about two degrees, thus the whole lot- of good eggs would be at 105 degrees, instead of 103 deg, and this would have a tendency to weaken the chicks, and thus prove a bad hatch. Whereas if the bulb is suspended just above the-eggs it will register the heat of the chamber and of all the good eggs. If it is impossible to suspend the thermometer, its position should be changed daily. .Then --we should get a more uniform reading right through the hatch. When two thermometers placed iii different places in the machine register slightly different, it does not always show that they are inaccurate, but perhaps that there is not a uniform heat in the Now I will , give a few reasons why chicks die in the shell. Fewer eggs would mean more fertile eggs, but this is not what we want, we want, more eggs- and better fertility at that. Suppose 100 fertile eggs were put in a machine and 70 hatched strong chicks, and the other. SO “Dead in Shell.” Well, it would be reasonable to suppose that; the fault lay with the eggs. The causes of -chicks dying in the shell are many and varied. If the eggs hatch well under the hens'and not in the machines, then look closely if you are operating the machine properly, and that your thermometer is' in proper order, as the temperature must not be constantly changing, all Lough a change from 4 to 5 degrees will do no harm. This must not occur too often, because no- machine will hatch well if it is constantly run- . ning from .100 to .105 degrees several times during the day. Cheap machines are .apt to cause much trouble in this respect. A small leak where lamp gas or smoke can get into the egg chamber, will also cause chicks to. die in shell. Thus -unsteady heat, too. .much or too little ventilation, over heated air that is dried out and causes the egg to dry out also, variations of heat, and smoke, leaks in the >egg. chamber, eggs from over fat or badly fed hens, thin or very thick, or badly shaped egg shells will cause chicks to die in the shell, but with ordinary, care and close attention to details, ■ combined with “common sense” we need have very little fear of this trouble, -but we must not forget to begin with the hen that lays the egg. When the chicks are hatching out keep the machine closed until all are hatched, this is important. If the machine has a nursery, as most of the best machines now have, the chicks can remain in that for 36 hours, then be removed to the brooder which should he .wanned up to 95 degrees for first two days. • Gradually diminish the heat down - to SO. degrees and keep at about that temperature.