Manure and faeces do not belong on the vegetable land, but on the compost heap.
The composition of manure and feces (Abortion) is so different, that you cannot fertilize with them according to plan. They also often contain ingredients, which can harm the vegetable plants. This is the best way to avoid it, that you spread this fertilizer on the compost heap and mix it in between when you work it. But if you still want to bring them to the country, then only in winter. They are distributed on the vegetable beds dug in the fall, but only then, when the ground is well frozen. Otherwise they would flood the upper layer of soil and the effect intended with the coarse ditch would not be achieved.