Distiller's Dried Grains with Solubles (DDGS) is a relatively common feed ingredient in poultry diets, but the total P content of DDGS is approximately twice that of the corn grain that it replaces in the diet. In this study we fed laying hens diets containing different amounts of DDGS and other dietary supplements (adipic acid and fumeric acid) to determine diet impacts on P excretion and P transformations during litter storage. Laying hens (Hy-Line W-36) 26 weeks of age were fed commercial diets containing 0 or 20 % DDGS, with and without adipic or fumeric acid for 8 weeks. Diets were formulated to contain similar crude protein, nonphytate P and calcium contents. Manure samples were collected four and eight weeks after diet initiation and divided into two equal portions for 14day storage experiments with or without 8.8 kg/ 100 m² of PLT^® (sodium bisulfite). Samples were collected after 0, 7 and 14 days of storage and analyzed for total P, HCl extractable P and water soluble P. The HCl extractable P and water soluble P were further fractionated into phytate P and inorganic P. The results and implications of this study will be presented in this poster.