Abstract DIFFERENCES among individuals in their ability to convert feed into body tissue are important in determining net income from the production of broiler chickens. However, measuring individual feed consumption is costly and time consuming. The result has been that most improvement in efficiency has come about as a correlated response to selection for growth. The associations among feed efficiency, growth rate, and feed consumption are complex and difficult to understand; however, it is extremely important that the industry has information regarding the effects of continuing to approach the subject as in the past. Therefore, the following important questions arise. What is the relationship between feed consumption and feed efficiency? To what extent is growth rate controlled by feed consumption and metabolic efficiency (the efficiency of an individual metabolic system in converting feed energy to body tissue)? Is metabolic efficiency genetically controlled and, if so, to what extent? What is the…