EFFECTS OF CAGE POPULATION ON THE PRODUCTIVE PERFORMANCE OF LAYERS

Two commercial layer strains (3,456 hens total) were used to examine the effects of bird population on productive performance. Four cage population sizes (6, 8, 12, and 24 birds per cage) were compared. All cages were 35.7 cm deep and varied in width (61.2, 81.6, 122.4, and 244.8 cm). Floor space per bird was 364.1 cm(2) and feeder space per bird was 10.2 cm in each cage configuration. Egg production and egg quality were measured from 20 to 72 wk of age. Strain differences were detected in hen-day egg production, egg mass, feed consumption, cracked egg percentage, Grade A eggs, Grade B eggs, peewee eggs, and large egg yield. There were no interactions between strain and cage population size. Cage population had no influence on hen-day egg production, mortality, feed conversion, egg size (peewee, small, medium, large, extra large), egg mass, lost eggs (by meat or blood spots), and percentage Grade B eggs. Percentage Grade A eggs, cracked egg percentage, and feed consumption were significantly influenced by cage population size. Hens housed at eight birds per cage had a greater percentage of Grade A eggs and a lower percentage of cracked eggs than those at other populations. Feed consumption was significantly greater for hens housed at 12 and 24 birds per cage compared with those at 6 and 8 birds per cage, respectively.