EFFECTS OF CAGE FLOOR SHAPE ON LAYER PERFORMANCE

Abstract

In a factorial split plot experiment, 1536 pullets were tested for 60 wk in four replications with two rearing systems (cage vs. floor), two genetic stocks, two population size-density combinations, and two cage shapes. Three and four Shaver 288 layers per cage were each tested at 464 cm2 and 542 cm2 per bird and three and four Hubbard Comets per cage each at 542 cm2 and 610 cm2 per bird. Layers were housed in both deep and shallow cages. Cage depth had no effect upon nervousness, feather wear (except for the wings), mortality, egg specific gravity, broken eggs or net egg returns over feed and bird costs. Birds in shallow cages had significantly less wing feather wear, laid more eggs, consumed more feed, had inferior feed conversion, larger body size and lower percentage of Grade A eggs. With the exception of the feathering on the neck, back and underside, there were no consistent two-and three-way interactions between the main effects. It was concluded that layers in shallow cages consumed more feed than required, gained an unnecessary amount of body weight and did not lay compensatory extra eggs. Feeding twice a day to provide continuity of supply may have stimulated layers in deep cages to consume enough food to equal the net egg returns of those in shallow cages. Possible reasons for the differences between the results at this station and elsewhere were also discussed.