Date of Graduation


Document Type


Degree Name

Master of Science in Poultry Science (MS)

Degree Level



Poultry Science


Susan E. Watkins

Committee Member

Fred D. Clark

Second Committee Member

K J. Rucker


Biological sciences, Chlorine, Oxidation reduction potential, Poultry, Sanitation, Water quality


A critical component in commercial poultry production is to ensure birds are provided clean, quality water. Multiple disinfectants can be utilized to optimize a good water quality program. The goal of these water disinfectants is to greatly reduce or eliminate the presence of all bacteria. In recent years, the oxidation-reduction potential (ORP) meter has been a tool utilized by the poultry industry to monitor chlorine efficacy in drinking water. An ORP reading of 650-750 millivolts (mV) has become the industry standard for assuring an acceptable sanitizing residual of free chlorine is present for controlling microbial contamination regardless of the actual amount of total or free chlorine or the water pH. A recent bench top evaluation of a new chlorine product revealed microbial contamination even when the oxidation-reduction potential read 650 mV. Given these results, it is beneficial for the poultry industry to re-evaluate the relationship between total chlorine residual, free chlorine residual, ORP value, and microbial levels. Additionally, the study determined if a new ORP standard should be the target and if this standard consistently correlates to free chlorine residual (ppm) even under scenarios of different water quality parameters. This study evaluated the efficacy of two different forms of chlorine, a liquid product (sodium hypochlorite) and a crystalline dry product (sodium dichloro-S-triazinetrione) at three concentrations (2, 4, and 8 oz/gal) commonly used for drinking water sanitation in the poultry industry. The objective was to determine the relationship between total and free chlorine residual, ORP, pH, and microbial content of the water when the chlorine products are utilized in water with a high microbial level typically found in unclean poultry drinking water lines. Results indicated both forms of chlorine were effective disinfectants for reducing aerobic bacteria present in the water. Additionally, the results of this experiment showed under field conditions where microbiologically challenged water is present, an ORP reading of 700 mV is required to achieve an efficient microbial reduction/elimination and this is supported by at least 3 ppm of free chlorine.