Five strains of broilers were reared in cages and in floor pens. The cages were arranged in four tiers in a back-to-back arrangement. Plastic mats were inserted over the wire floors in the finisher cages and conventional rice hull litter was used in the floor pens. Within the cage system, significant differences were found between strains, tiers, sex and the strain x sex interaction for 8-week body weight (P < 0.01). There were significant differences among strains as to enlarged feather follicles and mortality (P < 0.05); however, there were no significant differences (P < 0.05) among the strains for leg abnormalities. The heaviest broilers had the highest incidence of enlarged feather follicles and leg abnormalities. tne highest mortality (P < 0.05) occurred in the bottom tier ol cages, rloor reared broilers were not significantly different for 8-week body weight (P < 0.05) than cage reared broilers. Floor birds had negligible amounts of breast blisters, enlarged feather follicles and leg abnormalities.

Male broiler chicks were grown to 21 days of age under normal conditions, then placed in environmental chambers maintained under constant (24 C) or cyclic (24 to 35 C) heat conditions. Chicks were acclimated for 1 wk on a standard grower basal diet. Standard grower basal diets were fortified with 0, 125, 250, 500, or 1,000 ppm coated ascorbic acid (AA) or 0, 125, 250, or 500 ppm acetylsalicylic acid (ASA). Test diets were fed for 14 days in two separate studies. Cyclic heat conditions reduced feed intake and significantly reduced weight gains in both trials. Feed efficiency was not significantly affected by heat stress. Neither AA or ASA had beneficial effects on broiler growth or feed efficiency.

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