Masters Theses

Date of Award


Degree Type


Degree Name

Master of Science


Animal Husbandry

Major Professor

H. V. Shirley

Committee Members

O. E. Goff, R. L. Tugwell, J. K. Bletner


The use of drugs which alter the physiological reactions of the chicken may, at some time in the future, be as important as the prophylactic agents presently used in both broiler and layer rations. One of the ultimate goals of research is to find methods whereby the stress of continued domestication of the chicken might be minimized. Hediger (1955) suggests that if we look closely, it becomes clear that the primary reason for usefulness of the chicken as a domestic animal to man is not the hen's output, but rather the disappearance of the tendency to escape. The literature suggests that certain drugs classified as tranquilizers may alter the physiological process of the chicken without producing an anesthetic effect. Furthermore, the effects of these drugs are more apparent in the presence of stress. An agent which produces a stress reaction in an animal is any-thing to which the animal is unaccustomed. Probably the most prevalent stress factor in poultry production is extremes of environmental tempera-tures. High environmental temperatures adversely affect such economic factors as egg production, fertility and hatchability in hens, weight gains and feed conversion in broilers. Whenever handling of poultry is necessary it is advantageous to reduce the activity level of the birds in order to decrease the incidence of bruising and smothering and to facilitate handling in general. The ease of bruising and rate of healing has been shown by Hamdy et al. (1960) to be related to temperature. Poultry house temperatures in Tennessee may fluctuate drasti-cally. Temperatures over 100° F. and below zero are frequently experienced. It is of economic importance to the poultry industry to understand the ability of the chicken to withstand sustained high environmental temperatures, extremes of temperature and how resistance to these might be modified. It is imperative that new drugs be tested and compared for their ability to modify the behavior of the chicken in the presence of stress.

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