Chicken litter disposal is a major economic and pollution concern. Poor waste management practices lead to air and water pollution. To produce a useful renewable resource for energy, optimal conditions for combustion were studied. Three samples differing in particle size were obtained from the chicken litter by drying, milling, and sieving, each at a recovery of (A) larger than 150 mu m in size, 87.5%; (B) between 150 and 45 mu m in size, 6.3%; and (C) below 45 mu m in size, 6.3%. Sample A showed the highest calorific value (5300 BTU lb(-1) = 12320 kJ kg(-1)) and lowest ash content (ca. 25%), whereas sample C showed the lowest calorific value (2900 BTU lb(-1) = 6740 kJ kg(-1)) and highest ash content (ca. 54%). Evolved gas analysis (EGA) techniques, including thermogravimetric-mass spectrometry (TG-MS) and TG-Fourier transform infrared (TG-FTIR) were used to identify off-gases. Kinetic analyses using thermogravimetric analysis (TGA) were also performed to find that the combustion process proceeds in four stages (where E represents the activation energy): (I) release of absorbed water and ammonia stemming from ammonium salts (room temp (RT) = 150 degrees C), E = 61.72 kJ mol(-1); (II) devolatilization (150-350 degrees C), E = 71.43 kJ mol(-1); (III) char precombustion (350-500 degrees C), E = 148.5 kJ mol(-1); and (IV) rapid char combustion (500-650 degrees C), E = 157.6 kJ mol(-1). In stage III, the combustion is retarded because N concentration is high.