TURNING AND AIRING THE EGGS. 



8i 



by inexperienced hands. Some care should 

 always be exercised in selecting eggs for an in- 

 cubator. A few years ago they commonly died 

 if set when more than three or four days old, 

 showing that vitality must in some degree fall 

 off ; and most makers' prospectuses still state 

 that eggs over a week old are of little use. 

 Nevertheless, with improvements in machines, 

 eggs a fortnight and even three weeks old are 

 now often used, with results equal to those 

 obtained by the natural method in similar cir- 

 cumstances. No one questions, however, that 

 the freshest eggs are the best, though up to a 

 fortnight the chief difference is found to be in 

 somewhat later hatching. It is of more im- 

 portance to reject small or large eggs, and 

 especially those with rough or porous shells, or 

 any obvious fault at all in soundness of shell. 

 Some such eggs which might hatch under a hen 

 fail in an incubator, because of too rapid 

 evaporation. 



Proceeding from these fundamental details 

 of artificial hatching to the daily routine, it may 

 be well to explain that good results have been 

 hindered by several fashions or ideas, which in 

 succession have dominated those working in this 

 field, and which all of us more or less shared in 

 our time, the fact being that no one then knew 

 any better. Some of them are still believed in 

 by many, and several points in management, if 

 adopted, involve others. There has been a 

 cooling or " airing" era ; then a " carbonic-acid " 

 theory and consequent " ventilation " era ; and 

 (consequent really upon this last) finally came a 

 " moisture " era. It is curious now to reflect, that 

 all these might have been checked and moderated, 

 merely by adequate consideration of the egg- 

 ovens of Egypt. Let us proceed, however, to 

 consider practically the routine in detail. 



Unfailing regularity in trimming and filling 

 the lamp need hardly be insisted upon ; merely 

 the use of an oil inferior to that for which any 

 lamp is constructed, may give much trouble, 

 even if it does not cause failure, by creating 

 smoke and choking the flues. Flues and 

 chimneys should always be looked after at proper 

 intervals. A flat wick is best trimmed very 

 slightly convex on the top, or with the corners 

 very slightly taken off", when a rather tapered 

 flame much less liable to smoke is obtained. 

 When the flame is not too high, smoke usually 

 occurs from a high corner of the wick. Wicks 

 chemically prepared so as to need little trim- 

 ming during the whole of a hatch are now 

 largely used and supplied by the best incubator 

 manufacturers, and have greatly lessened one 

 of the most troublesome and tiresome portions 

 of incubator work. 



The first thing to see to in regard to the 

 eggs, is to turn them over regularly twice a day, 

 except at the very beginning and again at the 

 end. At the beginning, it is better 

 Turning and ^^ leavethem undisturbed, to heat up. 

 Moving the ^^^ ^1^^ twenty-four hours. A mark 

 should be made on the middle of the 

 side of each egg, that it may be seen how much 

 the egg is turned over. Some lay stress upon 

 turning the egg exactly half over each time ; 

 but as that brings the germ exactly to the same 

 spot in the shell every twenty-four hours, and 

 to the same portion of slightly evaporated 

 albumen, it cannot be beneficial. Most egg- 

 trays are lower in the centre ; the best way then 

 is to take out an egg from the lowest part, and 

 let the row above it roll very gently down the 

 hill, the whole row turning as it goes, placing 

 the egg taken out in the vacancy at the top. 

 The eggs will probably roll over rather more 

 than a third, but no exact aliquot part. The 

 same plan can be followed even in flat trays, 

 and it also saves time. But its greatest advan- 

 tage is that the eggs also change places, an egg 

 being taken from probably the hottest part of 

 the tray to the outside, and the others moved as 

 well as turned. It has been fully demonstrated 

 by systematic experiments that this is of great 

 importance. As already stated, no incubator yet 

 made is the same heat all over the tray, and those 

 which claim to be so are not even the best in 

 this respect. Changing places "evens" these 

 differences, and, as already mentioned, is regu- 

 larly carried out in the egg-ovens of Egypt, 

 and is even done by the hen herself. We have 

 marked many a hen-hatch to ascertain this, but 

 quote the following from an old correspondent : 

 "At 10.30 a.m. marked four eggs in the centre 

 of the nest. At 1.30 p.m. three marked eggs 

 were at the outside, one still at centre. Marked 

 three more in the middle. At 2.45 p.m. the 

 three last marked were moved to the outside, 

 and four marked first were also at the outside ; 

 marked four more left in the middle. At 4 p.m. 

 the four marked last were at the outside, and 

 some of those marked first were back in the 

 middle of the nest." Thus does even the hen 

 move her eggs from centre to outside of her 

 nest, and the average difference, as the result 

 of American experiments, is estimated at $ to 

 6 per cent, in favour of those so treated. 



This is one objection to the system of 

 " automatic " turning introduced in some in- 

 cubators; another being the tend- 

 Co^Ung"^ ency to return to identical positionj 

 already alluded to. But further, 

 the short cooling during the removal of the 

 tray to the outer air for this purpose, is actually 



