Two experiments were conducted with 6- to 10-wk-old turkeys. In Experiment 1, 6-wk-old turkeys were fed diets varying in level of fat (4.4 to 10%) or fiber (2.5 to 9.0%). The diets also contained extra copper as copper sulfate at either 0.1 or 0.2% of the diet. At 8 wk of age, 15 replicate birds were housed in individual cages and all excreta was collected. Excreta was separated as being “regular” or “cecal” in origin based on appearance. At 10 wk of age, 10 birds per treatment were killed and cecal contents removed under anaerobic conditions. Cecal contents were assayed for various nutrients and viscosity was measured. In a second comparable study, turkeys were fed animal-vegetable fat or regular or rancid canola oil (60.25 vs 120.24 ng/g malonaldehyde, respectively). In Experiment 1, feeding copper sulfate had the most noticeable effect on various cecal parameters. There was an increase (P < 0.01) in dry matter cecal droppings produced and the cecal contents were of increased viscosity (P < 0.05). Copper had no effect on pH or microbial colony count of the cecal contents. Feeding copper resulted in a significant increase in the high molecular weight (> 300,000) fraction of cecal contents and this fraction was of higher viscosity. Feeding copper sulfate resulted in a dramatic increase in copper content of cecal contents (280 to 11,848 ppm), although the copper content of regular excreta was also increased (17 to 1,008 ppm). The various levels of fiber and fat generally had no effect on cecal parameters. Feeding rancid canola oil did result in increased viscosity of cecal contents, compared to the situation seen with fresh canola oil. Fat rancidity per se, however, failed to influence other parameters such as total mass of cecal material produced and composition of cecal material. Feeding copper sulfate or rancid fat will increase the viscosity of cecal material, which may contribute to litter management problems.