ANIMAL PRODUCTION. 



77 



As the following table shows, the eggs of the pullets were smaller, less fertile, 

 tlie chicks smaller when hatched, the growth slower, and the deaths from 

 disease more numerous than was the case with eggs laid by mature fowls: 



FcrliliUj and hutchabUity of cf/pi^ in i/onnf/ and old foirls. 



Pullets 



2-year-old hens 

 3-year-old hens 



Pullets 



2-year-old hens 

 3-year-old hens 



Pullets 



2-year-old hens 

 .Vyear-old hens 



Pullets 



2-year-old hens 

 3-year-old hens 



Pullets 



3-year-old hens 



Pullets 



Old hens 



Youug fowls. . 

 Old hens 



Young fowls . . 

 Old hens 



Number 

 of eggs 

 incu- 

 bated. 



114 

 92 



8S 



110 

 110 



ISO 

 ISO 



ISO 

 180 



Weight 

 of eggs 

 per 100. 



Lbs. 

 11.50 

 12. 18 

 14.29 



11.71 

 12. 22 

 13! 16 



12.21 

 12. 04 

 13. 07 



9.95 

 13.50 

 13.30 



10.09 

 13.09 



10.30 

 13.04 



11.70 

 13.20 



12.10 

 12.50 



Per cent 

 unfertile. 



361 



Weight 

 of chicks 



per 100 

 at second 



weigh- 

 ing. 



Lbx. 



a 24. 70 

 27.60 

 35.00 



b 30. 74 

 37.32 



c 18. 35 

 25.17 



dl9.00 

 25. 40 



22. 60 

 26. 90 



a At 40 days after hatching. 

 6 At 46 days after hatching. 



c At 22 days after hatching. 

 d .\t 21 days after hatching. 



e At 26 days after hatching. 



In a trial with the incubator ventilators open and with an avera.ge maximum 

 and minimum outside temperature of 80° and 54.7° F., respectively, a better 

 hatch was obtained and the chicks were stronger when the eggs were not 

 cooled. Like results were obtained in a second trial with closed ventilators 

 and with a low external temperature. In 3 other tests with closed ventilators 

 and a high outside temperature the eggs not cooled hatche<l better than the 

 cooled eggs in 2 incubators, and not quite so well in one of another make, but 

 the chicks from the cooled eggs were stronger than the others in all 3 hatches. 

 This apparently indicates that in warm weather, when the circulation of air 

 in the incubator tends to l)ecome sluggish, it may be advisable to air the eggs 

 for a reasonable length of time. 



"It is difficult to conceive of any valid reason for cooling eggs during in- 

 cubation and tlius slowing down the vital processes. . . . The beneficial effects 

 which unquestionably sometimes arise from the process of cooling and airing 

 are due to the airing." 



In S tests which were made on the influence of moisture during incubation, 

 somewhat more chicks were hatched in the incubators operated without mois- 

 ture, but this result may have been due to the operator's more extensive ex- 

 perience in the use of the no-moisture machine. The loss in weight of the 

 eggs incubated without added moisture was very nearly normal, while in the 

 case of machines operated with moisture the loss was about two-thirds of the 

 norma!. In all cases the chicks hatched in the machine with added moisture 

 were heavier than the chicks hatched without added moisture, and apparently 



