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.
The amount of heat requisite to hatch the eggs is too much for the young birds already hatched and dried off. With chamber at 102 degrees, they will be seen crowding around the sides of machine with their little bills wide open, gasping for breath, when, had they been placed below, the proper temperature can be maintained in both, as the bottom of machine runs at least five degrees lower than the egg-trays.
Be sure and Follow Instructions.
Another fertile source of trouble is removing ducklings from machine, putting them behind the stove, or somewhere else to dry off. For every fifteen birds removed, the heat in egg-chamber is reduced at least one degree, as you are removing so many little stoves, and if the machine is not gauged higher, to correspond with the number of ducklings taken out, the result will be fatal to the unhatched eggs.
I corresponded a whole summer with one man on this very point before I found out what he was doing. He said he had never been able to get out more than fifty per cent. of fertile eggs. His machine ran splendidly until his chicks were about half hatched, when it would drop down to 90 degrees, and the rest would die in the shell, after they were nearly all pipped. At last a letter came from him stating that he had just had a worse experience than ever. He had a most promising hatch of three hundred fertile eggs, nearly all of which were pipped, and that, after a little more than half were hatched, he took them out as usual, about one hundred and fifty in number, and put them behind the stove to dry off, and his machine dropped to 90 degrees at once, and not another chick came out. The cat was out of the bag.
I wrote him at once that for every fifteen chicks he had taken out he had taken one degree of heat from his machine, and had he followed instructions he would not have suffered loss. He wrote back that he had shut up his machine for the season, but that he should run it one more hatch just to prove that I was wrong. At the end of three weeks a letter was received saying, "I tender you my hat. I got a splendid hatch of 88-1/2 per cent." Proving that occasionally there is danger of the operator knowing too much. After the ducklings are all out, the egg-trays should be removed, the valves opened, and the machine cooled down to 90 degrees, and the birds allowed to remain in the machine for at least twenty-four hours. I always cover the bottom of machine with an inch of fine wheat-bran, otherwise the ducklings would soon make it filthy and offensive. This acts both as absorbent and disinfectant.
After each hatch there will be more or less fertile eggs left in the trays with dead ducklings in them. There will be, comparatively, but few of these in the spring of the year, but during the latter part of the summer there will be more of them, and many of the eggs will have but little vitality in them.