Chicken manure has long been used as a fertilizer source. The nutrient composition of poultry manure/poultry litter "varies with the type of bird, the feed ration, the proportion of litter to droppings, the manure handling system and the type of litter" (North Carolina Cooperative Extension (CE)).
According to Oklahoma CE, "poultry litter is an excellent, low cost fertilizer if used properly" (PSS-2246). It releases nitrogen slowly and improves soil quality. Alabama CE says it "is the most valuable of all manures produced by livestock when properly handled."
I have read commentaries that chicken manure - "harvested" from concentrated animal feeding operations (CAFOs) where hundreds to thousands of chickens are raised in cages, given hormones, growth enhancers and antibiotics - may contain residual amounts of these chemicals as well as pathogens and pesticides.
One example of a commercial chicken manure product is a liquid product I recently heard about. I asked the manufacturer about how the product was produced, if the original manure source came from organic farms or from CAFOs and whether they processed it to eliminate pathogens. I was told that the product came from an organic farm. They supplied me with a chemical analysis that reported no E. coli or salmonella (pathogens). The product is certified organic by the USDA BioPreferred Program (www.biopreferred.gov) so it should also be free of pesticides. However, in its undiluted form, the product was fairly high in salts.
Is this or are other sources of poultry manure, for example, from your own or a neighbor's chickens, safe for vegetable production? "Due to the potential of transmitting human pathogens, such as E. coli, fresh manure should not be used on fruits and vegetables. On edible crops with soil contact (like carrots, beets, potatoes) fresh manure applications should be made at least four months prior to harvest. On other edible crops, fresh manure applications should be made at least three months prior to harvest" (Colorado State CE).
In general, chicken manure is considered to have the highest nutrient content of animal manures. If you apply manure within 60 days of harvest, reduce the risk of disease by using only manure that has been aged for at least a year or hot-composted manure (internal temperature of 140° or greater). If buying packaged manure, whether solid or liquid, the container should tell you whether it is pathogen-free. Wash all raw vegetables thoroughly before eating them. People with weakened immune systems, those with chronic diseases, children or pregnant women should avoid eating any uncooked vegetables fertilized with animal manure.
JoAnne Skelly is the Carson City/Storey County Extension educator for University of Nevada Cooperative Extension and may be reached at firstname.lastname@example.org or 887-2252.