Last update: April 5, 2012 10:32:19 AM E-mail Print


Fowl Manure Rich In Nitrogen And Phosphorus



FOWL manure is a valuable by-product on the farm. As it is richer in nitrogen than any other animal manure, it is important that special precautions be taken to minimise losses, particularly of nitrogen, during storage.

A hundred hens each weighing an average of 5 lb. will produce approximately 4,250 lb. of manure in a year. This manure would contain 43 lb. of nitrogen, 16 lb. of potassium and 34 lb. of phosphoric acid. According to Morrison, the average composition of various kinds of fresh manure is as shown in Table 1.

In the fruit- and vegetable producing areas of the Union fowl manure is scarce and expensive and some farms keep large flocks of birds mainly for manure they produce.

As a result of incorrect methods of storage, fowl manure unfortunately often loses much of its value.



Often large piles of manure are found in the open and quite unprotected. Manure exposed in this way loses much of its value through leaching and fermentation. Unfortunately the most soluble constituents are lost first.

Good quality fowl manure is richer in nitrogen than any other farm manure, but if allowed to decompose, a large percentage of the nitrogen may become lost in the form of ammonia. This can, however, be prevented in various ways. One of the most successful of these is the daily addition of one pound of super phosphate to the manure of every ten hens.

As our soils are usually deficient in phosphorus it is essential to add adequate amounts of this element. Not only does the addition of super phosphate to the manure prevent the loss of ammonia to a large extent, it also provides phosphorus so that the manure becomes a balanced fertiliser.



To prevent the deterioration of fowl manure, it should be kept under shelter. In an intensive poultry farming system where fowls are kept in houses, a few alterations to the building will make it possible to collect and store large quantities of clean fowl manure indoors and so minimise deterioration.

Poultry houses in which the birds roost above the manure pits and which are built in such a way that the fowls do not come in contact with the manure, are fairly common.

A thick layer of straw is placed on the concrete floor between two manure pits. The required number of nests is also provided in this part of the house.

It should be noted that the hens spend most of the day above the manure pit. The advantage of such houses is that a large amount of clean manure collects in the pit. A further advantage of such a system is that the houses are cleaned only once a year, which saves a considerable amount of labour.

During the year clean straw is added to the litter material only when necessary.




In the United States research workers have found that where poultry houses are provided with manure pits only, about 35% of the total quantity of manure is deposited in the pits. Where feed hoppers and drinking troughs are provided in addition to the manure pit 75% of the manure is collected.

At the Grootfontein College of Agriculture hens from three breeds - Black Australorp, White Australorp and Rhode Island Red - were placed in three identical houses equipped with manure pits, feed hoppers and drinking troughs. After six months the manure was removed from the pits and weighed separately. As the manure was very dry, it was easy to handle.

Table 2 shows the total quantity of manure in the pits of the three individual houses, as well as the percentages of manure in the pits and on the floor.

In Table 2 it is assumed that in the course of a year the hens will produce an average of 45 lb. of manure each. (The percentages of manure in the pits and on the floor correspond with findings in the United States).

Table 3 shows the total quantity of clean manure in the pits and on the floor.

Table 3 shows very clearly that of the possible quantity of manure which 133 hens can produce in one year, 72.2% collected in the pits as clean manure, and that 133 hens, given proper housing, can produce more than two tons of clean manure in a single year. Calculated at £7 per ton, the hens produced manure to the value of £15 in a year.

A comparison of the average egg production per house (after six months) with the percentage of manure in the pits, is given in Table 4.

According to Table 4 there is positive correlation between egg production and the amount of manure in the pits. The higher the egg production, the more manure collects in the pits. This is explained by the fact that heavy layers eat and drink more than the others and consequently spend more time at the feed hoppers and water troughs above the pits during the day.



Farming in South Africa 35 (10)