368 EXPERIMENT STATION RECORD. 



Poultry experiments, J. Dryden {Utah Sta. Bui. 102, pp. 203-228. fif/s. ,S).— 

 Coutinuiiig earlier work (E. S. R., 17, p. 390) studies were made of the effects 

 of housing ou egg fertility and of the effects of a number of conditions during 

 incubation on the proportion of eggs which hatched, and related questions. 



The average fertility of eggs laid by hens in a house artificially heated in 

 winter and in an open-front house was each 70 per cent, in a house with no 

 artificial lit-at 77 per cent, and in a colony house with free range 74 per cent. 

 The i)erceiitage of fertile eggs hatched ranged from 33 with the hens in a house 

 artificially heated to 55 in the case of those in an open-front house, and the 

 weight per egg from 1.89 oz. in the case of pullets in an open-front house to 

 2.15 oz. in the colony house with the free range. On the whole the results are 

 in favor of the colony house as regards egg yield. The fowls in the colony 

 house had free range, and in every other case they had access to yards, and 

 during the winter, when snow was on the ground, were given no water. " They 

 a])parently did not suffer from the eating of snow or the lack of water." 



In tests to determine the eft'ect of medium and maximum moisture content 

 of the air of incubators as compared with no moisture, it was found that 

 "Nearly 100 per cent better hatches were obtained by the use of moisture, and 

 there was no contradiction in all of the tests." Tlie I'elative humidity of the 

 air in the "no moisture" machines was about 51° and in the other incubators 

 about 57°. The relative weiglit of the chickens liatched in the " maximum 

 moisture " incubator was 1.184 oz.. in the " medium moisture " incubator 1.159 

 oz., and in the " no moisture " incubator 1.072 oz. The weight of a hen-hatched 

 chick was 1.258 oz. The results of these weighings " would indicate that vigor 

 in the chicks demands a greater amount of moisture during incubation than 

 the incubator, as at present made, can furnish." The author also believes that 

 proper germ development does not take place unless the humidity conditions 

 are favorable, for the records obtained sliow^'that a larger number of eggs 

 were removed as infertile or having dried germs from the dry than fi-om the 

 moist -incubatoi-s. 



The evaporation from the eggs in the machine with maximum moistui'e was 

 12.28 per cent, in that with medium moisture 14.05 per cent, and in that with 

 no moisture 17.78 per cent. 



When trays of water were used as a source of moisture instead of trays of 

 moistened sand, the relative loss of weight in eggs during incubation was 16.13 

 as compared with 12.28 per cent. "The sand is therefore more effective as an 

 evaporating surface than water." 



Tests were made of the amount of carbon dioxid in the air of the incubators, 

 but in the author's opinion the values obtained apparently do not bear any 

 relation to the number of chicks hatched. Tests of the air under sitting hens 

 showed Ml.l parts of carbon dioxid per 10.000 parts of air, and practically 

 the same amounts of carbon dioxid were found with a hen sitting on china 

 eggs as on heus' eggs, so " there seems to be no question from these results 

 that the hen gives off large quantities of carbon dioxid from her body." The 

 fact that in incubators the carbon dioxid found comes largely from the eggs, 

 while in natural incubation it comes from the hen's body " indicates a vital 

 difference in the conditions of artificial and natural incubation." Ou the 

 whole, the investigations " have shown large quantities of carbon dioxid in 

 natural incubation and relatively small amounts in artificial incubation, but 

 increasing artificially, the supply of carbon dioxid seems rather to have an 

 injurious effect in artificial incubation." 



Poultry division, F. B. Linfield (Montana Sta. Rpt. 1906, pp. 12Ji-127).— 

 Improvements in the station poultry plant are described and the egg records of 

 14 pens of station poultry recorded. The iirincipal object of the station poultry 

 work is the development of large laying strains of different breeds. 



