Experiment 8 was conducted as a repetition of Experiment 7. The same 

 commercial White Leghorn stock was used. Duplicate groups of 117 sexed 

 pullet chicks were started in March, 1956. for each feeding treatment. The 

 chicks were brooded to 8 weeks of age, moved to range where they re- 

 mained until 22 weeks of age, at which time they were housed. 



An all-mash feeding system was used for the experiment. Starting mash 

 was fed to six weeks of age at which time a change was made to growing 

 mash. While on range the feed was in pellet form. At 23 weeks of age 

 breeder mash was fed. 



Since in the previous experiment with Leghorns the feed restriction 

 approximated 20 percent, this degree of restriction was studied in this 

 experiment. Feed restriction was practiced from six to 23 weeks of age. 



The data from Experiment 8 is presented in Table 3 together with the 

 data from Experiment 7. 



Attention is now called to the fact that all experiments thus far re- 

 ported here were conducted with a uniform minimum 14-hour day by 

 means of artificial lighting, regardless of season of the year, or age of 

 the chickens. This procedure resulted from original research at this sta- 

 tion (10,11) demonstrating that fall-hatched pullets could be delayed 

 approximately two weeks in sexual maturity by use of a uniform 14-hour 

 day. Since application of artificial light is one of the simplest management 

 practices to use. this procedure was used throughout the experiments. In 

 addition, to measure only feeding effects, it was desirable to eliminate light 

 effects in so far as practicable. Skoglund (12) has shown that, depending 

 upon date of hatch, sexual maturity may be delayed by as much as one 

 month when artificial lighting was not used. 



Since proper application of artificial light and restricted feeding each 

 have an effect in delaying sexual maturity. Experiment 9 was designed to 

 measure whether these effects were additive. 



For Experiment 9 a November. 1956, hatch of chicks was used, since 

 it is the fall hatches which are most stimulated to earlv sexual maturity 

 by natural daylight. To measure the combined effects of 14-hour lighting 

 and restricted feeding, this treatment was compared with a program of 

 natural daylight and full feeding. A meat strain of White Plymouth Rock 

 chicks was used. Triplicate pens of 42 pullet chicks each were used for 

 the experiment. Feed restriction was started at 6 weeks and continued to 

 20 weeks of age at which time the full fed pullets were in production. 

 Other management practices were the same as used in previous experi- 

 ments. 



The results of Experiment 9 are presented in Table 4. 



Results and Discussion 



The results from the first two experiments, presented in Table 1, in which 

 feed restriction was practiced on a time basis, show that feed restriction 

 was only moderate. In fact, after 16 weeks of age, little restriction was 

 evident in Experiment 3. This may have been true at an earlier age in Ex- 

 periment 3 and possibly also in Experiment 1. However, experimental 

 methods in use at the time did not accumulate the necessary data. 



In Experiment 3 at 16 weeks of age it was noted that feed restriction 

 was slight between 12 and 16 weeks of age. For this reason weekly feed 



10 



