The Box Type of Incubator In Actual Use.

Although the fact is not so advertised and frequently not recognized even by the makers, the success of existing incubators is directly proportional to the extent with which they control evaporation. In order to show this I have only to call attention briefly to two or three of the most successful types of incubators on the market.

Let me first repeat that evaporation increases with increased air currents and with decreased vapor pressure. Now, the vapor pressure undergoes all manner of changes with the pa.s.sing of storm centers and the changes of prevailing winds. But there is a general tendency for vapor pressure to increase with increase in outside temperature.

Now, the movement of air in all common incubators depends upon the draft principle and the greater the difference in machine temperature and outside temperature the greater will be this draft.

Thus, we have two factors combining to cause variation in the rate of evaporation. The tendency for the rate of airflow to vary is diminished when a cellar is used for an incubator room, but the cellar does not materially remedy the climatic variation in vapor pressure.

The general tendency of incubators as ordinarily constructed, is to dry out the eggs too rapidly. With a view of counteracting this, water is placed in pans in the egg room. A surface of water exposed to quiet air does not evaporate as fast as one might think, as is easily shown by the fact that air above rivers, lakes and even seas is frequently far from the saturation point. The result of the moisture pan with a given current of air is that the vapor pressure is increased a definite amount, but by no means is it regulated or made uniform. Inasmuch as too much shrinking is the most prevalent fault in box incubators, the use of moisture is on the whole beneficial, but in hot, murky weather, with less circulation and higher outside vapor pressure, the moisture is overdone and the operator condemns the system.

The subject not being clearly understood and no means being available for vapor pressure determinations, the system results in confusion and disputes. When the felt diaphragm machine was brought into the market it was advertised as a no-moisture machine. The result of the diaphragm is that of choking off air movement and consequently reducing evaporation. This gives exactly the same results as the use of moisture, but the machine is easier to operate and seemed to do away with the vexatious moisture problem which, together perhaps, with some fancied resemblance of felt diaphragms to hen feathers, has resulted in the widespread use of this type of machine.

The latest effort along the lines of reducing evaporation is the sand tray machine that followed in the wake of the Ontario investigation. This device simply gives a greater evaporating surface to the water and hence a greater addition to the vapor pressure. The results in practice I had given me by a man who last year hatched sixty-five thousand chicks and as many more ducklings.

He said: "The sand tray early in the season gave the best hatches and most vigorous chicks we had, but later on things got too wet and the chickens drowned." No nicer demonstration of science in practice could be desired.

In the present-day incubator of either type we are wholly at the mercy of sudden climatic changes of vapor pressure. For the slower changes from season to season some control by greater and less amounts of supplied moisture, or by ventilator slides is available, but little understood and seldom practiced.

It will certainly be of interest to my readers to know the actual hatches obtained with the prevailing type of box incubator. By actual hatches we mean the per cent. of live chicks taken out of the machine to the per cent. of eggs put in. The ordinary published hatches, based on one per cent. of fertile hatches, are a delusion and a snare. When eggs are tested out many dead germs come out with them and the separation of microscopic dead germs from the infertile egg is, of course, impossible. Such padded and show hatching records do not interest us.

Where incubators are run on top of the ground I have found the results to be poor and to improve, the bigger and deeper and damper and warmer and less ventilated the cellar is made. The reason for this is plain. In such a cellar the vapor pressure of the air is not only greater but is less influenced by the shifting vapor pressure of the outside air. In a good cellar the operator, though his knowledge of the factors with which he deals is grievously deficient, learns, through long and costly experience, about what addition of moisture or about what rate of ventilation will give him the best results. In the room more subject to outside influences, the conditions are so constantly changing that uniformity of practice never gives uniform results, and hence the operator is without guidance, either intelligent or blind, and the results are wholly a product of chance.

As proof of my contention I may give results of a series of full season hatches for 1908, each involving several thousand eggs.

First, a state experiment station, the name of which I do not care to publish. Incubators kept in a cement bas.e.m.e.nt which has flues in which fires were built to secure "ample ventilation." This caused a strong draft of cold, dry air, making the worst possible condition for incubation. The hatch for the season averaged 25 per cent. and was explained by lack of vitality in the stock.

Second, Ontario Agricultural College. A room above ground, moisture used in most machines and various other efforts being made to improve the hatches by a staff of half a dozen scientists. Results: Hatch 48 per cent.--incubator manufacturers call the experimenters names and say they are ignorant and prejudiced.

Third, Cornell University: dry ventilated bas.e.m.e.nt representing typical conditions of common incubator practice of the country.

Results: Hatch 52 per cent., results when given out commonly based on fertile eggs and every one generally pleased.

Fourth: One of the most successful poultrymen in New York State, who has, without knowing why, hit upon the plan of using a no-moisture type of incubator in a bas.e.m.e.nt which is heated with steam pipes, which maintains temperature at 70 degrees and has a cement floor which is kept covered with water. Results: Hatch 59 per cent.

Fifth: As a fifth in such a series I might mention again the Egyptian machine with the uniform vapor pressure of the climate and the three chicks exchanged for four eggs.

While an official in the United States Department of Agriculture, I gathered data from original records of private plants covering the incubation of several hundred thousand eggs. Such information was furnished me in confidence as a public official and as a private citizen I have no right to publish that which would mean financial profit or loss to those concerned.

Of records where there were ten thousand or more eggs involved, the lowest I found was 44 per cent. and the highest, that mentioned as the fourth case above, or 59 per cent. The great majority of these records hung very closely around the 50 per cent. mark.

The following is a fair sample of such data. It is the record of hatching hen eggs for the first six months of 1908, at one of the largest poultry plants in America:

Eggs Chicks Per Cent.

Month Set Hatched Hatched

January 4,213 1,585 37 2-3 February 6,275 2,339 33 3-4 March 17,990 6,993 38 1-3 April 18,819 10,265 54 1-2 May 24,458 14,438 59 June 13,100 6,614 55 ------ ------ ------ Total 84,855 42,234 50 p.c.

The Future Method of Incubation.

The idea of the mammoth incubator which would hatch eggs by the hundred thousand and a minimum of expense is the dream of the American incubator inventor. We have long had available such methods of insulation and regulating the supply of heat as would point to the practicability of such a dream.

The past efforts in this direction have fallen down for the following simple reason: All eggs were placed in a single big room with a view of the man's entering the room to take care of them.

Contact with cold walls, the opening of doors, the hatching of chicks or introduction of fresh eggs set up air currents, the hot air rising and the cold air settling until great differences in temperature would be found in the room. No systematic regulation of evaporation was contemplated, as the principles at stake or the means of such regulation were unknown.

The attempt just referred to was made several years ago by one of the most successful of incubator manufacturers and because of his failure other inventors were inclined to steer clear of the proposition. Meanwhile the need of such an incubator has grown enormously. At the time that above effort was made no duck ranch existed whose annual production ran over thirty or forty thousand ducklings, whereas we now have several in the one hundred thousand cla.s.s.

Much more remarkable has been the growth of the day-old chick business. The discovery that newly hatched chicks could be successfully shipped hundreds of miles with less loss than shipping eggs for hatching, has resulted in a few years' time in the growth of hatcheries of considerable size where chicks are hatched by means of common incubators. Still another opportunity for the use of large hatcheries has been by the growth of poultry communities. There are other communities besides those mentioned in this book which would amply support public hatcheries. If half the poultry growers of Lancaster County, Pa., were to be prevailed upon to patronize a public hatchery, the county would support between fifteen and twenty 100,000 egg incubators. Any of the numerous trolley centers in Indiana, Ohio and Southern Michigan would likewise be profitable locations for the establishment of public hatcheries.

The demand for the incubator of large capacity has, within the last year or so, brought two or three "mammoth" incubators into the market. The devices I now refer to consist of a row of box incubators which, instead of being heated by single lamps, are heated by continuous hot water pipes. This scheme effects a considerable saving in fuel cost and labor, but the bulkiness of construction and the woeful lack of evaporation control are still to be dealt with.

The writer now wishes briefly to describe the plan of construction and operation of a new type of hatchery, the success of which has recently been made feasible by inventions and technical knowledge hitherto unavailable. The plan of the hatchery is on that of a cold storage plant as far as insulation and general construction go. The eggs are kept in bulk in special cases which are turned as a whole and may rest on either of four sides. At hatching time the eggs are spread out in trays in a special hatching room, which is only large enough to accommodate chicks to the amount of one-sixth of the incubator capacity, for twice a week deliverings, or one-third if weekly deliveries are desired.

There are no pipes or other sources of heat in the egg chambers. All temperature regulation is by means of air heated (or cooled as the case may be) outside of the egg rooms and forced into the egg rooms by a motor driven cone fan, maintaining a steady current of air, the rate of movement of which may be varied at will. The air movement maintained will always be sufficiently brisk, however, to prevent an unevenness of temperature in different parts of the room.

So simple is this that the reader will doubtless wonder why it was not developed earlier. The reason is that air subject to the climatic influences will, with any forced draft sufficient to equalize temperature, result in a fatal rate of evaporation.

Sprinkling the air has not generally been thought practical because of the notion that air must not be used in the egg chamber but once, which involved quite a waste of heat necessary in warming a large bulk of air and evaporating sufficient water. Moreover, no means has, in the past, been available for making a sufficiently accurate measurement of the evaporating power of the air.

The hair hygrometers commonly sold to incubator operators are known by scientists to be absolutely unreliable. The range between the wet and dry bulb thermometers was found in the Ontario experiments to give readings with and without fanning that varied 15 to 20 per cent. in relative humidity which, at the temperature of an egg chamber, would amount to a variation of three to four hundred of vapor pressure units, which, with the forced draught plan, would ruin a hatch of eggs in a few hours. The sling psychrometer as used by the U.S. Weather Bureau should, in the hands of an expert, give results making possible measurements accurate to two or three per cent. of relative humidity or forty to sixty units of vapor pressure. In contrast with these blundering instruments we now have available an instrument with which the writer has frequently determined vapor pressure accurately to within a range of two or three vapor pressure units and the instrument is capable of being constructed for even finer work.

As it is only by means of air with the moisture content absolutely controlled that the use of a large room becomes possible, we can now see why this type of hatching remained so long undeveloped. By means of such vapor pressure control the large egg chamber is not only feasible but the rate of evaporation at once becomes subject to the control of the operator and we achieve a perfection in artificial incubation hitherto unattained.

The means by which the air moisture is regulated is similar to that used in up-to-date cold storage plants where the air is made moist by sprinkling and dried with deliquescent salts. The regulation of vapor pressure, like that of temperature, may be by electrically moved dampers which switch a greater or less proportion of the incoming current to the sprinkler or dryer as the case may be. The ordinary incubator thermostat gives the necessary impulse for the control of the temperature dampers, while the instrument above referred to is used for the vapor pressure control.

As the entire air circuit is closed, the chemical composition of the air may also be regulated at will. This results in a reduction of the quant.i.ty of heat required to a minimum; in fact, with the incubator in full swing, the air will, at times, need cooling rather than warming.

The question of the cost of incubation by this method, or of profit of such a hatchery operated for the public is almost wholly one of the size of operations. Where sufficient eggs may be obtained and sufficient demand exists for the chicks to make it profitable to operate, the additional cost of hatching extra chicks will be insignificant compared with the present system.

The Egyptian poultryman gives four eggs for three chicks, but the American poultryman would be willing to give four eggs for one chick, as is shown by the fact that he sells eggs for from 1 to 3 cents apiece and buys day-old chicks for ten to fifteen cents. A plant with a seasonable capacity of 100,000 eggs has a basis to work upon something as follows:

With a fifty per cent. hatch and chicks at 10 cents each there would be a gross income of $5,000 annually. From this we must subtract for eggs at 2 cents each, $2,000. Salary for operator $1,000, wages for helper $300. Fuel, supplies and repairs $500. Cost of delivery and sales of chicks $200. This leaves a residue of $1,000, which would pay a 20 per cent. interest on the necessary investment of $5,000.

Personally, I think this is about the minimum unit of hatching that would prove worth while as independent inst.i.tutions.

Any increase in the percentage of the hatch would, of course, reduce the unit of size necessary for profitable operation. Upon a single poultry plant as a duck farm the cost of operation would be materially reduced, as the operator himself would take the place of the intelligent manager and the cost of gathering eggs and the delivery of the product would be eliminated.

The most profitable method of hatchery operation undoubtedly will be upon a plan a.n.a.logous to what, in creamery operation, is called centralization. The success of this scheme depends upon the fact that transportation and agencies at country stores are relatively less important items of expense than plant construction and high salaries for skilled labor. A hatchery with a million capacity can be built and run at not more than twice the cost of one hundred-thousand plant and better men can be kept in charge of it. A portion of the saving will of course be expended in maintaining a system of buying eggs and selling chicks.

The material advantage of operating a hatchery in connection with a high-cla.s.s egg handling and poultry packing establishment, or as one feature of a poultry community, is at once apparent, for the system of collecting the market produce will be utilized for gathering eggs and distributing chicks, each business helping the other.

The public hatchery also gives an excellent opportunity for the introduction of good stock among farmers who would be too shiftless to acquire it by ordinary methods.

CHAPTER VII

FEEDING

The old adage that a little knowledge is a dangerous thing is nowhere better ill.u.s.trated than in the scientific phases of poultry feeding. The attempted application of the common theoretical feeding standards to poultry has caused not only a great waste of time but has also resulted in expenditures for high-priced feeds when cheaper feeds would have given as good or better results.