Effects of floor versus cage rearing and feeder space on growth, long bone development, and duration of tonic immobility in single comb White Leghorn pullets.

The effects of feeder space on growth of commercial layer pullets reared in cages or floor pens were examined by allocating 1-d-old chicks to either cages (14 chicks) or floor (119 chicks). Feeder spaces were 5.4, 4.0, and 2.7 cm per pullet and were held constant throughout the growing period, resulting in a 2 x 3 factorial arrangement. Measurements of pullet body weight, feed consumption, skeletal development, and fearfulness were taken through the rearing period to 18 wk. Pullets allowed 5.4 cm of feeder space were heavier (P < .001) (1,329 g at 18 wk of age) than birds allowed either 4.0 or 2.7 cm of feeder space (1,289 and 1,272 g, respectively). Floor-reared pullets weighed significantly more at 12, 16, and 18 wk of age than cage-reared pullets. Feed consumption was not affected by the feeder space, but the floor-reared birds consumed more (P < .001) feed than those in cages (61.2 vs 52.8 g per pullet per d). Mortality, skeletal development, and bone strength were not affected by either feeder space or floor vs cage rearing. Floor-reared pullets had longer (P < .05) duration of tonic immobility (TI) than those reared in cages (519.7 and 471.4 s, respectively, as measured at 18 wk). Feeder space per pullet had no effect on the duration of TI of the pullets. Cage and floor rearing environments are comparable for rearing pullets provided feeder space is not restricted to such an extent as to inhibit BW.