Abstract: A method to prepare an organic composition for a digestor minimizes injury to and enhance the decomposition function of anaerobic and facultative anaerobic bacteria in the organic composition. The method is utilizes at an animal processing facility. Manure produced at the facility is periodically collected at least seven day intervals and at a temperature greater than thirty-two degrees F. Large pieces of inorganic material are removed from the manure while preserving a significant proportion of the living anaerobic and facultative anaerobic bacteria in the manure. The decomposition activity of anaerobic and facultative anaerobic bacteria is facilitated by, at a temperature in the range of fifty degrees F to one hundred and five degrees F, adding water to produce a slurry including seventy-five to ninety-five percent by weight water and twenty-five to five percent by weight of organic material.