86 



THE BOOK OF POULTRY. 



membrane, even though things were right in the 

 main. Many of these things often happen in a 

 nest of eggs under a hen, and are simply brought 

 into higher rehef with an incubator, owing to 

 the number involved, and the fact that they are 

 then ahvays supposed to be the fault of the 

 machine or of the management, which is, how- 

 ever, by no means always the case. Some of the 

 causes are only partially within human control 

 in a practical sense. 



Duck eggs require a little different treatment 

 to get the best results ; they can be hatched 

 with others, but the average is not 

 Duc^Eggs. so good as when separate. It is 

 generally agreed that a little lower 

 temperature is better; but the difference depends 

 upon the machine. Mr. Hearson advises two 

 degrees less, and somewhat the same may be 

 necessary whenever the capsule is higher than 

 the eggs, and there is a cold moist bottom tem- 

 perature. With American hot-air machines, 

 \ialf a degree to one degree less is more usual. 

 Where free ventilation and free moisture are 

 used, a little more moisture during the last few 

 days, not before, is also generally better for 

 duck eggs ; but the size of the air-cell, as 

 already described, must be studied in reference 

 to this. Many large operators also think more 

 airing or cooling advisable, but taking care to 

 close the drawers whilst the trays are out, in 

 order that they may heat up again as quickly 

 as possible. The following remarks on in- 

 cubating duck eggs have been furnished us 

 for publication by Mr. Henry E. Moss, at one 

 time manager of Mr. Morgan's great duck 

 ranch, which was situated at Riverton, Virginia. 

 We had observed from our study of American 

 poultry papers, that while 50 per cent, of live 

 ducklings to eggs seemed about the general 

 American average,* Mr. Moss's were consider- 

 ably higher, and by common notoriety were 

 above those obtained by other raisers of duck- 

 lings on the large scale practised in the States. 

 His incubators were all on the hot-air principle, 

 and it will be seen that he writes rather differ- 

 ently from other breeders concerning both 

 moisture and cooling. 



" The artificial incubation of duck eggs differs 

 very materially from that of the eggs of other 

 fowl. It does not follow that eggs from what- 

 ever source will respond to the same treatment, 

 and yet many large duck farmers in this country 



* This average may seem low ; but it is to be remembered 

 that a large quantity of the eggs are winter-laid, and most of 

 them from ducks kept in large families, some in large flocks, for 

 economy in management. Under these circumstances the 

 fertility of the eggs themselves is heavily discounted. Our own 

 " early breeders " know best how p luch such an average, on 

 thousands hatched, really means. 



have for years persisted in doing this very thing. 

 The writer has for some years been making a 

 practical and thorough study of this question. 

 Operating from thirty to forty incubators each 

 season on duck eggs, studying cause and effect, 

 and reasoning deductively rather than induc- 

 tively, he has achieved a greater measure of 

 success than has previously been recorded, and 

 while not fully prepared yet to describe every 

 detail, will briefly make clear some of the 

 important points. 



" The first and most important requirement 

 is proper heat. It is necessary in order to obtain 

 the best results to maintain a uniform and un- 

 varying degree of heat at the upper surface of 

 the egg. This uniform degree of heat should 

 rest on every egg alike. This is a condition 

 which never has and perhaps never will be found 

 perfectly attained, in any commercial incubator. 

 Incubators do their best work when run in an 

 underground room, or cellar, or cave, where a 

 uniform temperature of about 65'' can be main- 

 tained ; otherwise, uniformity will depend upon 

 the efficiency of the thermostat. After the 

 machine has been slowly and thoroughly heated, 

 and then held steady for twenty-four hours at 

 100° with the thermometer lying on the tray, 

 the bulb free, you are ready for the eggs. 

 During the first forty-eight hours do not disturb 

 them, but as soon as they are in the machine 

 turn on rather more flame, and get the heat up 

 quickly to the proper degree, which is 102'^, the 

 thermometer resting upon the eggs, the top of 

 the bulb on a level with the top of the eggs. As 

 soon as the heat is up to 102", see that the 

 damper-valve is slightly raised, and then turn 

 down the flame low enough to just hold the 

 damper up a trifle. If the room is subject to a 

 sudden fall in temperature, however, adjust the 

 flame a little higher than ordinary, so as to be 

 prepared for the emergency, and trust to the 

 heat-regulator. 



" During the first few days, and before the 

 animal heat develops in the egg, adjust the trays 

 by raising or lowering, if necessary, so as to 

 secure the same reading on all the thermometers. 

 When this is done do not change their elevation 

 again, no matter what difference may seem to 

 exist, but change position of the trays daily, in 

 order to average variations in temperature. 



" The first test can be made about the sixth 

 day, the second on the sixteenth, when if the 

 development has advanced ,, as it should, the 

 allantois will have nearly or quite encircled the 

 embryo, rendering the egg nearly opaque. After 

 forty-eight hours begin the regular turning twice 

 a day. Do not jar the eggs, but handle very 

 carefully. After testing replace the trays so as to 



