“…Some commonly used additives that improve growth rate or improve utilization of broiler feeds include bacitracin, in the form of either zinc bacitracin or bacitracin methylene disalicylate (Bird, 1968;Coates and Harrision, 1969;Creek and Schumaier, I960;Damron et al, 1975;Fernandez et al, 1973;Heuser and Norris, 1952;Matterson and Singsen, 1951;Stutz et al, 1983), and 3-nitro-4-hydroxyphenylarsonic acid [roxarsone (Abbott et al, 1954;Bird et al, 1949;Carlson et al, 1954;Frost, 1953;Libby et al, 1955;Milligan et al, 1955;Morehouse, 1949;Morehouse and Mayfield, 1946;Waldroup et al, 1984;West, 1956;Wharton and Fritz, 1953)]. Damron et al (1975) reported that there was no interaction between zinc bacitracin and roxarsone in regard to body weight gains or feed utilization by broilers.…”