POULTRY KEEPING.

Auckland Star, Volume LVII, Issue 162, 10 July 1926, Page 24

POULTRY KEEPING.

(By R. J. TEKKX.)

TO CORRESPONDENTS.

OKriXGTON (Epsom) is worried because the eggs from her heus huve a taste of stalenpss. Would it lie possible for the heus to retain the eggs and so become tainted, or would it be because we have given them some blood aud bone which we use for the garden? We were told that was good for fowls.—lt is possible for heus to retain an ess till it is bad, but that is ouly if the heu is very fat; but the eggs laid by all your fowls being the same would be proof that the taste of staleness is due to the blood and bone manure that you are feeding. It is very unwise, especially when you are feeding the eggs to children, to feed blood and bone which is manufactured for use as manure, aud would probably contaiu blood and meat from condemned animals. If you discontinue it the eggs will not be flavoured with it after about four days. BAY OF ISLANDS thinks that I have written at some time that bran need not be fed to the same extent if the birds have lucerne.—That is quite correct. If your birds have au unlimited amount of luce-rue you ran cut down the bran ration easily by a half. Two pounds of greeu lucerne leaves equal about oue pound of bran. INCUBATION. I have been asked something about incubation somewhat on the lines that I wrote two or three years ago so that beginners may get a better grip of the process of artificial incubation. The rocks on which most beginners get wrecked is, ventilation and moisture. We can dismiss at once the question of temperature. Any good make of machine will see to this. In testing eggs for fertility on the fifth or sixth day the novice can sol- through the shell of the egg when held in front of a light in a darkened room, what is termed the spider, which is really the eye of the chick which shows up dark and that which looks like a web, is really a system of blood vessels. All those who use incubators know that in testing eggs on the fifth day, instead of finding what is termed the spider when you look through the shell, in many cases there is an irregular ring of blood. It used to be and is still thought by many that this was due to the eggs having been shaken in transit, but if one fills an incubator directly from the nests, and you carry them yourself so that you are certain that the eggs have not received the slightest concussion, you will still find in certain makes of incubators a number which show the blood ring denoting a ruptured blood vessel. It is unnecessary for mc to go into details of the years of research, work till I have proved to the incubating world that an excess of pure air in the early stages of incubation is harmful. Briefly, the oxygen in the pure air unduly increases the circulation with a result— ruptured blood vessels. I further claim that where there is an excess of fresh air through the machine during the embryonic stage that the chicks from the hatch will not have the frame and bone as those chicks will have where the circulation has been retarded in the first week or ten days of incubation. To give you a year's work in a few words: CO2, by which is meant, carbon dioxide of the air plays a very important part in both natural and artificial incubation. I will give you a little experiment which you can perform for yourselves and you start to know something about carbon dioxide. Take a bottle and put in it a candle. Melt a little of the wax in the bottom of the bottle set the candle in the wax, then li«rht the candle. Take a rubber tube.

put one end down into the bottom of the bottle and breathe into that bottle the air which comes from your lungs. One good long breath or two will extinguish the candle, showing the air which is exhaled is in a different condition from when it was inhaled. No, you don't blow the candle out. Now, the power of the exhaled air to extinguish the candle is due to an ingredient known as carbon dioxide, which is breathed out by all animals. The same substance is found in large quantities in the atmosphere under a hen sitting on an ordinary nest. The ' carbon dioxide in conjunction with moisture has the effect of decomposing , (or rotting, as it might be more familiarly termed) the shell of the egg thus rendering it an easy matter for a fully developed chick to break it. CarI bon dioxide converts the carbonate of lime which forms the shell of the egg, which is insoluble in ordinary water into ; bicarbonate of lime, which is soluble in ordinary moisture or water; and experts now acknowledge that a considerable portion of the shell of the egg is absorbed by the growing embryo and builds up the frame of the chick. This is the chief reason why in many cases chicks hatched under hens are supposed to have tetter constitutions than those hatched by incubator. Most makers of inctibators have, since my first article appeared in 1908, considerably reduced the ventilation and advised the closing or partial closing of ventilators till after the fifth or eixth day, and this is correct. There is far less risk with the ordinary ma-cbine with ventilators closed in the early stages of the hatch, and 1 must again impress upon Uiose using incubators that the clucks do not breathe through their lungs till shortly prior to breaking out of the shell. If we go back to ancient Egypt, it lias been learned that artificial incubation was carried on in a very large way. Unfortunately we do not seem able to ascertain as much knowledge as regards the working of these incubators as one would wish, but what information has been gathered goes to prove that they are run on practically the same lines to-day as they were a few thousand years ngo. They are really caves or large chambers, and the gas given off must be tremendous. In a hot country sucli as Egypt, there would naturally be a fair amount of bad eggs brought in, but even apart from this, nothing can grow without producing carbonic gas. To go for a moment from artificial to natural incubation, we find further proof that carbonic gas it not harmful. The wild turkey of Queensland, together with some other birds, do not set or incubate their own eggs, but they gather together a mass of vegetable matter, the eggs are deposited in the middle of the heap, and are hatched by the heat generated by the fermentation of the decay of vegetable matter, which must give off a considerable quantity of carbonic gas. Where is the circulation over or around the eggs or the current of pure air so often advocated. Of course, it is quite a different matter in the later stages of incubation when the rotting of the shell has taken place, and the bird will soon be breathing through its lungs. The mere fact of turning tUe eggs in the early stages and the slight cooling they get is sufficient ventilation, as the air in the air cell changes by contracting when it is cold and expand-1 ing wlien it is heated, and Nature has made provision for extra air as the entbrj'o grows by enlarging the air cell.