Three experiments were conducted to study the nutritional value of poultry litter in ruminants and poultry. In the first experiment, eight yearling wethers were used in a series of three metabolism trials to study the utilization of the nitrogen in autoclaved peanut hull broiler litter containing 32.6% crude protein (dry matter basis). Poultry litter nitrogen replaced 25, 50 and 100% of the nitrogen of a purified diet containing isolated soybean protein as the nitrogen source. Apparent digestibility of crude protein in the rations decreased significantly at each increase of litter nitrogen level beyond 25%. However, the depression of crude protein digestibility at 50% litter nitrogen level was small. Digestibility of the litter nitrogen, calculated by difference, was 67 and 64%, respectively at 25 and 50% level of the nitrogen, which were not much lower than 71% when only soy protein was used. Nitrogen retention and percent utilization of absorbed nitrogen were significantly lower at the 100% litter-N level than when no litter was used. There were no consistent differences in the nitrogen fractions of the rumen fluid and blood plasma among the rations. In the second experiment, three digestion and metabolism trials were conducted with 10 yearling wethers to study the protein and energy utilization of autoclaved peanut hull and woodshaving broiler litters when each was incorporated in corn-hay natural ration at levels of 25 and 50 percent. Apparent digestibility of crude protein did not show any significant difference among the rations. Crude fiber digestibility of the litter rations was higher than that of the control ration. Dry matter, NFE and energy digestibility were lower (P<.01) for the litter rat:ons and decreased significantly when the litter level in the ration was increased from 25 to 50%. No significant difference was observed in nitrogen retention, due to kind or level of litter in the rations. Crude fiber digestibility, calculated by difference, was significantly depressed when the level of litter was increased from 25 to 50%. There were no other significant differences in digestibility between kind or level of litter. The apparent digestibility of crude protein was 71.7%. Digestible protein content (on dry matter basis) for peanut hull and wood shaving litter were 23 and 22%, respectively. The average TDN value for ooth kinds of litter was 60% (dry basis). Average digestible energy values (kcal./kg. on dry matter basis) were 2472 and 2407 respectively for peanut hull and wood shaving litter. The corresponding values for metabolizable energy were 2212 and 2150 kcal./kg. There was no significant difference in digestible protein, TDN, digestible energy, and metabolizable energy values due to kind or level of litter. The third experiment was conducted to study the value of different levels of processed peanut hull litter as a partial protein supplement in a practical type broiler ration. When 1/6 or 1/5 of the protein in the basal diet was replaced with litter crude protein by the inclusion of 13.9 or 16.7% litter in the diet, there was no significant difference in rate of gain, compared to the control. When 1/4 of protein in the basal diet was replaced by litter crude protein (20.8% litter in the diet), a significant growth depression resulted. Feed efficiency of the litter fed groups was significantly lower than that of groups on the basal diet. / Ph. D.