The Effect of High Levels of an Antibiotic on Laying Chickens During Hot Weather

Abstract

THERE is disagreement among the results obtained at different experiment stations on the effect of antibiotics on the egg production and hatchability of chickens. An interesting possible explanation for part of the disagreement was offered by Lillie and Sizemore (1954), who found that supplementing a diet with an antibiotic improved the egg production of low- but not of high-producing New Hampshires.Some of the more recent reports are on experiments with layers kept under what can be considered “stress” conditions. Balloun (1954) found that the addition of chlortetracycline at the level of 50 mgm. per pound of diet improved egg production “under conditions unfavorable to high egg production.” White-Stevens (1954) reported that the addition of chlortetracycline at the level of 100 grams per ton of diet increased egg production and hatchability in the presence of chronic respiratory disease.A further review of the literature does not seem pertinent to the …