The metabolizable energy values of various fish meals for chickens have been determined directly by Olsson (1950), Hill and Renner (1957), and Potter et al. (1962). Calculated values for fish meals have also been determined (Titus, 1955). Several experiments have been conducted to determine the practical value of poultry by-product meal, hydrolyzed poultry feathers, and poultry oil in chick diets. However, few experiments have been reported on the determined metabolizable energy values of these ingredients. Metabolizable energy values for feed grade tallow have been reported by Renner and Hill (1960), and for yellow grease by Wilder et al. (1959) and Young (1961).Seven experiments, involving 128 groups of chicks, have been conducted to determine the metabolizable energy values of 13 different fish meals, four poultry byproduct meals, five feather meals, five poultry oils, and a sample each of feed-grade tallow and yellow grease. Each of these ingredients was incorporated into …