1028 



Recent Research in Egg Production. 



[Feb., 



They compared White Leghorns with general purposes breeds, 

 and found that the latter reached their maximum rate of pro- 

 duction early in the season and then rapidly fell off to 

 moderate production, whereas the White Leghorns reached 

 their maximum production a month or so later, but continued 

 to produce heavily for several months, and then fell off rapidly 

 towards the end. Experiments in this country are required 

 before these conclusions can be accepted as applicable to our 

 climatic conditions; it may be possible to alter the time of year 

 of greatest productivity by providing shelter and other condi- 

 tions which would modify the natural tendency of the White 

 Leghorn to attain its maximum production later in the spring 

 than the " sitting " breeds. 



The Copenhagen trials^ 14 ) showed that Plymouth Rocks laid 

 more eggs than Leghorns during the winter months. At first 

 sight this might seem to contradict the statement made above, 

 that high-producing hens lay more eggs in the winter months, 

 but it possibly may be due to the fact that Plymouth Rocks go 

 broody and so reduce the summer yield (see " Broodiness " 

 above, p. 1026). 



Effect of Egg Production on Body Weight of Hen.— The 



effect of high egg production on the body weight of the hen 

 was studied at the Copenhagen trials, and it was found that, 

 although the weight of the birds increased with age up to the 

 end of the second year, yet within each year the weight of the 

 hen's body undergoes certain variations. Increase in weight 

 takes place from the autumn to the spring, and then during 

 the spring and summer the weight decreases. This seasonal 

 change in weight was especially noticeable in good layers. 



Kirkpatrick and CardO- 7 ) also found that hens were heaviest 

 on 1st March, before the period of maximum egg production, 

 and lightest on 1st Mav, after the period of maximum produc- 

 tion. In this connection the observations of Wieninger^ 26 ) 

 are interesting; he found that within any one breed the best 

 layers had the lowest body weight. Thus, in a flock of Golden 

 Wyandottes he noticed that the best layers averaged 2-4 kilos 

 in weight, whereas the worst layers averaged 2-6 kilos. In the 

 Italian Partridge breed the best averaged 21 kilos and the 

 worst 24 kilos (a kilogram is 2 l-5th lb.V 



Attempts have been made at the Harper Adams College (27 ) 

 to discover some relationship between the shape of the bird 



(26) Wiener Landw. Ztg., No. 26, 1912. 



(27) Utility Poultry Journal. Harper Adams College. No. 12, 1917-18. 



