Duck manure is great for the compost pile and as long as it looks "well rotted" by sitting until it has decomposed it is safe to use. The amount of time this takes depends on what else is in the compost (green waste speeds things up) and what size the pile is and the weather conditions. In general composting manures in a pile without turning or aerating are not used on the garden for at least a year. Keep growing, Marianne Binetti