Effects of rearing relationships, cage size, and bird density on performance of two commercial strains of eggtype chickens. Poultry Sci

ABSTRACT Two commercial strains of White Leghorn-type pullets, reared in colony cages from 12 to 21 weeks of age, were subjected to various treatments in cages involving rearing relationship, cage size, and bird density. At 21 weeks all birds were moved to different cages; half housed as penmates (reared in the same cage) and half as intermingled (reared in separate cages). Two cage sizes (72 X 82 and 41 X 41 cm.) and two densities (330 and 590 cm. of cage floor area per bird) were used. Birds that died were not replaced. Traits measured were mortality, egg production, age of sexual maturity, and egg quality. No significant differences were noted for the effect of housing method on the parameters studied. However, birds housed as penmates tended to out perform those intermingled, sug-gesting that strangeness may have a small effect on performance. Mortality was not signifi-cantly affected by the parameters studied. Egg production was significantly affected by strain, cage size, and density. The highest rate of lay (78%) was from the small cage-low density combination; lowest rate (70%), from the large cage-high density combination. A cage size X density interaction, which resulted from density differences being greater than cage size differences, was observed for hen-day and hen-housed egg production. Birds housed in large cages matured 4 days later than those in small cages. A cage size X density interaction showed birds housed in large cages at high density maturing 8 days later than those in small cages at high density. Egg quality and bird weights were not affected by the parameters studied, except for a strain effect on egg quality