SUMMARY AND CONCLUSIONS 



One of the problems which has plagued the poultry industry throughout 

 the years has been that of cannibalism. Broiler growers are constantly faced 

 with serious losses in income due to the lower price they receive when 

 bare-backed broilers are marketed. Theories have been advanced by some 

 investigators that light intensity might play an important role in canni- 

 balism among chickens as well as upon other characteristics. 



Two series of experiments were conducted at the University of New Hamp- 

 shire. In the first series, the effect of light intensity and daily light dosage 

 on broilers was investigated. Measurements made were feather picking on 

 the back, body weight, feed conversion, mortality rate, and uniformitv of 

 bodv weight. Reflector-type flood light bulbs were used to provide light 

 intensities of 15, 60, and 120 foot candles, measured at the height of the 

 feeder, and the daily light dosages were 12 and 24 hours. 



There was no evidence of feather picking in this series of experiments. 

 Neither was there any significant difference among groups with respect 

 to body weight, feed conversion, mortality rate, and uniformity of body 

 weight. 



Based on the results of the first series of experiments a second series 

 was established in which the two extremes of light intensities, 15 and 120 

 foot candles, w'ere compared and combined with two feed forms, mash and 

 pellets, and two floor space allotments. 1 square foot and -•>, square foot. 

 Once again it was demonstrated that light intensity itself has no effect 

 upon feather picking under conditions of this experiment, but birds fed 

 pellets or allowed -3 square foot per bird tended toward increased feather 

 picking. The pellet-fed groups had higher body weight and significantly 

 superior feed conversion compared to the mash-fed groups. Body weights 

 from the lower light intensity groups were heavier than those from the 

 higher light intensity groups. 



Within the limits of the experiments reported here the following conclu- 

 sions are drawn: 



1. When broilers were fed feed in mash form and allowed 1 square foot 

 of floor space per bird, neither daily light dosages of 12 or 24 hours, nor 

 light intensities of 15, 60 and 120 foot candles had any significant effect 

 in inducing cannibalism as expressed by feather picking on the back. 



2. The light intensities and light dosages mentioned above had no effect 

 upon body weight, feed conversion, mortality rate, or uniformity of body 

 weight. 



3. Use of either pelleted feed or a floor space allotment of -3 square 

 foot per bird resulted in a significant increase in feather picking. 



4. In the second series of experiments in contrast to results in the first 

 series, the body weights of the lower light intensity (15 foot candles) groups 

 were heavier than those of the higher light intensity (120 foot candles) 

 groups, but the difference was not statistically significant. 



5. Use of pelleted feed resulted in heavier bodv weight and superior 

 feed conversion, though the difference in body weight was not statistically 

 significant. 



6. Light intensities, feed forms and/or floor space allotments had no sig- 

 nificant effect upon mortality rate or uniformity of body weight. 



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