Manure Nutrient Production from Commercial White Leghorn Hens

Considerable difference exists in the literature regarding the nutrient concentration of and amount of manure produced by laying hens. Because nutrient management laws and regulations can restrict the number of birds per farm, values that reflect current management practices of today's commercial hens are critical. In a 2-yr field study, eight commercial flocks were selected to measure the manure nutrient concentration and production of Leghorn hens. Total amount of manure (in tons) and manure N, P2O5, K2O, Ca, Mg, and moisture concentrations were determined. Weekly production records served to calculate nutrients entering the hen house as feed and leaving as nutrients in manure, eggs, mortalities, and body weight gain. The results suggest that modern hens produce less manure than literature values would imply. Approximately 40% of feed N is lost to the atmosphere, while about 70% of dietary P and K are deposited with the manure, and dietary Ca is almost equally divided between the manure and egg shell. Regression equations from the field results significantly predicted manure production as well as P, K, and Ca concentrations utilizing easily gathered data such as feed nutrient levels, feed consumption, and egg mass produced.