CHANGES IN EGG PRODUCTION. 



117 



Changes in Amount of Broodiness. 

 This phase of breeding for increased egg production has been discussed 

 in another place (Goodale, 1920). Here it is sufficient to recall that, while 

 some birds lay continuously throughout spring and summer without any 

 marked slowing in rate of production, others lose much time on account 

 of broodiness, — a loss that very clearly is not compensated for. 



^80 



o 20 



SEP 



OCT. 



NOV 



DEC. 



JAN. 



FEB. 



Fig. 13. — Daily Production of Two Pens of the Same Breeding, 1920-21. 

 Heavy line, April hatched; light line, late hatched. 



Note. — The records of this flock v/ere made under quite different conditions and meth- 

 ods of management from those made by the other flocks. A priori, they appeared to 

 be considerably .sub-optimal, but the results show that they were at once correct and 

 simple. A brief description of the conditions and methods of management follow. 



The 50 females and 6 males were in a pen 22 by 11, 6 feet high at the plate and 10 at the 

 ridgepole, made by stretching w-ire netting across the south side of a second-story 

 barn floor. A windbreak of paper extended 3 feet from the floor. Roosts v/ere at the 

 west. The main opening was a pitch hole about 4 feet square in the south side. 

 Additional light came from a window 2 feet square in the gable, plus some light from 

 two openings in other parts of the loft. A little sand was put on the floor and straw 

 used as a litter. The birds had water and open boxes of dry mash constantl.y before 

 them. Oyster shell was fed on the floor. No special grit was fed. Three to 4 pounds 

 of cracked corn were fed in the morning, and double that amount at noon. Green 

 sprouted oats ad libitum (165 square inches) were fed at noon. Droppings accumulated 

 on the floor back of a wire litter stop. Besides gathering the eggs and keeping straw in 

 the nests and the litter distributed (the latter mostly done by feeding the cracked 

 corn where it was thickest), no other attention was given. The caretaker was away 

 during the day. 



The loss due to broodiness is shown when the seasonal production of 

 a broodj^ race is compared with that of a non-broody race. The maximum 

 production of a broody flock comes in March. April is nearly as high, 

 but during May and June, corresponding to the period of progressive 

 increase in the number of broody birds, production declines sharply to a 

 level that either remains nearly constant for July, August and September, 

 or in which the descent is much less marked. (See Fig. 4, 1915-16 and 



